View source for Japanese aircraft carrier Akagi

{{short description|Aircraft carrier of the Imperial Japanese Navy}}
{{other ships|Japanese ship Akagi}}
{|{{Infobox ship begin}}
{{Infobox ship image
|Ship image=AkagiDeckApril42.jpg
|Ship caption=''Akagi'' conducting flight operations, April 1942
}}
{{Infobox ship class overview
|Name=
|Operators={{navy|Empire of Japan}}
|Class before={{ship|Japanese aircraft carrier|Hōshō||2}}
|Class after={{ship|Japanese aircraft carrier|Kaga||2}}
|Cost=
|Built range=1920–1927
|In service range=1927–1942
|In commission range=1927–1942
|Total ships completed= 1
|Total ships lost=1
}}
{{Infobox ship career
|Hide header=
|Ship country=[[Empire of Japan]]
|Ship flag={{shipboxflag|Empire of Japan|naval}}
|Ship name=''Akagi''
|Ship namesake=[[Mount Akagi]]
|Ship operator=
|Ship ordered=1920
|Ship awarded=
|Ship builder=[[Kure Naval Arsenal]]
|Ship original cost= [[Japanese yen|¥]]53 million ($36.45 million)
|Ship yard number=
|Ship way number=
|Ship laid down=6 December 1920
|Ship launched=22 April 1925
|Ship sponsor=
|Ship christened=
|Ship completed=
|Ship commissioned=25 March 1927
|Ship reclassified=21 November 1923 as an aircraft carrier
|Ship refit=24 October 1935&nbsp;– 31 August 1938
|Ship struck=25 September 1942
|Ship fate=Damaged by aircraft during the [[Battle of Midway]] and [[Scuttling|scuttled]], 5 June 1942
}}
{{Infobox ship characteristics
|Hide header=
|Header caption=(after 1938 modernization)
|Ship class=None
|Ship type=[[Aircraft carrier]]
|Ship displacement=*{{convert|36500|LT|MT|lk=on}} ([[Displacement (ship)#Standard displacement|standard]])
* {{convert|41300|LT|MT}} ([[deep load]])
|Ship length={{convert|260.67|m|ftin|abbr=on}}
|Ship beam={{convert|31.32|m|ftin|abbr=on}}
|Ship draught={{convert|8.71|m|ftin|abbr=on}}
|Ship power=*19 [[water-tube boiler]]s
* {{convert|133000|shp|kW|abbr=on|lk=on}}
|Ship propulsion=4 shafts; 4 geared [[steam turbine]]s
|Ship speed={{convert|31.5|kn|lk=in}}
|Ship range={{convert|10,000|nmi|lk=in|abbr=on}} at {{convert|16|kn}}
|Ship complement=1,630
|Ship armament=*6 × single [[20 cm/50 3rd Year Type naval gun|{{convert|20|cm|abbr=on|1}} guns]]
* 8 × twin [[12.7 cm/40 Type 89 naval gun|{{convert|127|mm|abbr=on}}]] [[AA gun]]s
* 14 × twin [[Type 96 25 mm AT/AA Gun|{{convert|25|mm|abbr=on|0}} AA guns]]
|Ship armor=*[[Belt armor|Belt]]: {{convert|152|mm|abbr=on}}
* [[Deck (ship)|Deck]]: {{convert|79|mm|in|abbr=on}}
|Ship aircraft=*66 (+25 reserve)
* 21 [[Mitsubishi A6M Zero]]
* 18 [[Aichi D3A]]
* 27 [[Nakajima B5N]] (7 Dec 1941)
|Ship aircraft facilities=
|Ship notes=
}}
{{Infobox service record
|is_ship=yes
|label=
|partof=[[1st Air Fleet (Imperial Japanese Navy)|First Air Fleet (''Kido Butai'')]]
|codes=
|commanders=*[[Isoroku Yamamoto]] (1928–29)
* [[Ryūnosuke Kusaka]] (1939–40)
* [[Kiichi Hasegawa]] (1941–42)
* [[Taijiro Aoki]] (1942)
|operations=*[[Second Sino-Japanese War]]
* [[World War II]], [[Pacific War]]:
** [[Attack on Pearl Harbor]]
** [[Battle of Rabaul (1942)|Invasion of Rabaul]]
** [[Bombing of Darwin]]
** [[Battle of Java (1942)|Invasion of Java]]
** [[Indian Ocean raid]]
** [[Battle of Midway]]
|victories=
|awards=
}}
|}
{{Nihongo|'''''Akagi'''''|赤城|lead=yes||"Red castle", named after [[Mount Akagi]]}} was an [[aircraft carrier]] built for the [[Imperial Japanese Navy]] (IJN). Though she was [[Keel laying|laid down]] as an {{sclass|Amagi|battlecruiser}}, ''Akagi'' was converted to an aircraft carrier while still under construction to comply with the terms of the [[Washington Naval Treaty]]. The ship was rebuilt from 1935 to 1938 with her original three [[flight deck]]s consolidated into a single enlarged flight deck and an [[Glossary of nautical terms (A-L)#island|island]] superstructure. The second Japanese aircraft carrier to enter service, and the first large or [[Fleet carrier|"fleet" carrier]], ''Akagi'' and the related ''[[Japanese aircraft carrier Kaga|Kaga]]'' figured prominently in the development of the IJN's new carrier striking force doctrine that grouped carriers together, concentrating their air power. This doctrine enabled Japan to attain its strategic goals during the early stages of the [[Pacific War]] from December 1941 until mid-1942.

''Akagi''{{'}}s aircraft served in the [[Second Sino-Japanese War]] in the late 1930s. Upon the formation of the [[1st Air Fleet of the Imperial Japanese Navy|First Air Fleet]] or ''Kido Butai'' (Striking Force) in early 1941, she became its [[flagship]], and remained so for the duration of her service. With other fleet carriers, she took part in the [[Attack on Pearl Harbor]] in December 1941 and the [[battle of Rabaul (1942)|invasion of Rabaul]] in the Southwest Pacific in January 1942. The following month, her aircraft [[Bombing of Darwin|bombed Darwin, Australia]], and assisted in the [[Dutch East Indies campaign|conquest of the Dutch East Indies]]. In March and April 1942, ''Akagi''{{'s}} aircraft helped sink a British [[heavy cruiser]] and an Australian [[destroyer]] in the [[Indian Ocean raid|Indian Ocean Raid]].

After a brief refit, ''Akagi'' and three other fleet carriers of the ''[[Kido Butai]]'' participated in the [[Battle of Midway]] in June 1942. After bombarding American forces on [[Midway Atoll|the atoll]], ''Akagi'' and the other carriers were attacked by aircraft from Midway and the carriers {{USS|Enterprise|CV-6|2}}, {{USS|Hornet|CV-8|2}}, and {{USS|Yorktown|CV-5|2}}. A single [[dive bomber]] from ''Enterprise'' severely damaged ''Akagi''. When it became obvious she could not be saved, she was [[scuttling|scuttled]] by Japanese destroyers to prevent her from falling into enemy hands. The loss of ''Akagi'' and three other IJN carriers at Midway was a crucial strategic defeat for Japan and contributed significantly to the Allies' ultimate victory in the Pacific. Her wreck was located in 2019 by the [[RV Petrel|Research Vessel ''Petrel'']].

==Design==
===Construction and launch===
{{see also|Amagi-class battlecruiser}}
''Akagi'' was laid down as an {{sclass|Amagi|battlecruiser}} at [[Kure Naval Arsenal|Kure, Japan]], on 6 December 1920. Construction was halted, however, when Japan signed the [[Washington Naval Treaty]] on 6 February 1922. The treaty placed restrictions on the construction of battleships and battlecruisers although it authorized the conversion of two battleship or battlecruiser hulls under construction into aircraft carriers of up to {{convert|33000|LT|t|lk=on}} displacement. The IJN had decided, following the launch of its first aircraft carrier, {{ship|Japanese aircraft carrier|Hōshō||2}}, to construct two larger, faster carriers for operations with major fleet units. The incomplete hulls of {{ship|Japanese battlecruiser|Amagi||2}} and ''Akagi'' were thus selected for completion as the two large carriers under the 1924 fleet construction program.<ref name="l8">Lengerer, p. 128</ref><ref>Peattie, p. 54; Watts, p. 171; Jentschura, Jung and Mickel, p. 36; Parshall and Tully, pp. 6–7</ref> ¥24.7 million was originally budgeted to complete ''Akagi'' as a battlecruiser and an estimated ¥8 million had been expended when construction stopped in February 1922. Shortly thereafter, the [[Diet of Japan|Diet]] approved an additional ¥90 million to complete ''Akagi'' and ''Amagi'' as carriers.<ref>Parshall and Tully, pp. 7, 535</ref> Her guns were turned over to the [[Imperial Japanese Army]] for use as [[coastal artillery]]; one of her main-gun turrets was installed on [[Iki Island]] in the [[Strait of Tsushima]] in 1932.<ref>Gibbs, p. 217</ref> The rest of her guns were placed in reserve and scrapped in 1943.<ref>Gibbs & Tamura, pp. 192, 194</ref>

[[File:Japanese aircraft carrier Akagi 1925.jpg|thumb|left|''Akagi'' on 6 April 1925, prior to her launch at Kure]]
Construction of ''Akagi'' as an aircraft carrier began on 19 November 1923. ''Amagi''{{'}}s hull was damaged beyond economically feasible repair in the [[1923 Great Kantō earthquake|Great Kantō earthquake]] of 1 September 1923 and was broken up and scrapped.  ''Akagi'', the only remaining member of her class, was launched as a carrier on 22 April 1925 and commissioned at Kure Naval Arsenal on 25 March 1927, although trials continued through November 1927. She was the second carrier to enter service with the IJN, after ''Hōshō'' and before {{ship|Japanese aircraft carrier|Kaga||2}} (which replaced ''Amagi'').<ref name="l8"/><ref>Watts, p. 65; Jentschura, Jung and Mickel, p. 36</ref>

Since ''Akagi'' was initially conceived as a battlecruiser, the prevailing [[Japanese ship naming conventions|ship naming conventions]] dictated that she (like her sister ships) be named after a mountain. ''Akagi'' came from [[Mount Akagi]], a dormant volcano in the [[Kantō region]] (the name literally means "red castle"). After she was redesignated as an aircraft carrier, her mountain name remained, in contrast to ships like {{ship|Japanese aircraft carrier|Sōryū||2}} that were originally built as aircraft carriers, which were named after flying creatures. Her name was previously given to the [[Japanese gunboat Akagi|''Maya''-class gunboat ''Akagi'']].<ref>Goldstein, Dillon and Wenger, p. 8</ref>

''Akagi'' was completed at a length of {{convert|261.21|m|ft|sp=us|0}} [[length overall|overall]]. She had a [[beam (nautical)|beam]] of {{convert|31|m|ftin|sp=us}} and, at [[deep load]], a [[draft (ship)|draft]] of {{convert|8.08|m|ftin|sp=us}}. She displaced {{convert|26900|LT|MT}} at ([[Displacement (ship)#Standard displacement|standard]]) load, and {{convert|34364|LT|MT|-1}} at full load, nearly {{convert|7000|LT|MT|-2}} less than her designed displacement as a battlecruiser.<ref name="l9">Lengerer, p. 129</ref>  Her complement totaled 1,600 crewmembers.<ref name="pt463">Parshall and Tully, p. 463</ref>

===Flight deck arrangements===
''Akagi'' and ''Kaga'' were completed with three superimposed flight decks, the only carriers ever to be designed so. The British carriers converted from "large light cruisers", {{HMS|Glorious||2}}, {{HMS|Courageous|50|2}}, and {{HMS|Furious|47|2}}, each had two flight decks, but there is no evidence that the Japanese copied the British model. It is more likely that it was a case of convergent evolution to improve [[launch and recovery cycle]] flexibility by allowing simultaneous launch and recovery of aircraft.<ref>Brown, p. 2</ref> ''Akagi''{{'}}s main flight deck was {{convert|190.2|m|ftin|sp=us}} long and {{convert|100|ft|m|order=flip|1|sp=us}} wide,<ref>Peattie, p. 229</ref> her middle flight deck (beginning right in front of the bridge) was only {{convert|15|m|ftin|sp=us}} long and her lower flight deck was {{convert|55.02|m|ftin|sp=us}} long. The utility of her middle flight deck was questionable as it was so short that only some lightly loaded aircraft could use it, even in an era when the aircraft were much lighter and smaller than during World War II.<ref name="l30">Lengerer, p. 130</ref> The upper flight deck sloped slightly from amidships toward the bow and toward the stern to assist landings and takeoffs for the underpowered aircraft of that time.<ref name="Peattie, p. 54">Peattie, p. 54</ref>

[[File:JapaneseAircraftCarrierAkagi3Deck cropped.jpg|thumb|left|''Akagi'' on trials off the coast of [[Iyo, Ehime|Iyo]], 17 June 1927, with all three flight decks visible]]
As completed, the ship had two main hangar decks and a third auxiliary hangar, giving a total capacity of 60 aircraft. The third and lowest hangar deck was used only for storing disassembled aircraft. The two main hangars opened onto the middle and lower flight decks to allow aircraft to take off directly from the hangars while landing operations were in progress on the main flight deck above. The upper and middle hangar areas totaled about {{convert|80375|sqft}}, the lower hangar about {{convert|8515|sqft}}. No catapults were fitted. Her forward [[Elevator#Aircraft elevators|aircraft lift]] was offset to starboard and {{convert|11.8|x|13|m|ftin|sp=us}} in size. Her aft lift was on the centerline and {{convert|12.8|x|8.4|m|ftin|sp=us}}. The aft elevator serviced the upper flight deck and all three hangar decks. Her [[arresting gear]] was an unsatisfactory British longitudinal system used on the carrier ''Furious'' that relied on friction between the arrester hook and the cables. The Japanese were well aware of this system's flaws, as it was already in use on their first carrier, ''Hōshō'', but had no alternatives available when ''Akagi'' was completed. It was replaced during the ship's refit in 1931 with a Japanese-designed transverse cable system with six wires and that was replaced in turn before ''Akagi'' began her modernization in 1935 by the Kure Model 4 type (Kure shiki 4 gata). There was no island superstructure when the carrier was completed; the carrier was commanded from a space below the forward end of the upper flight deck.<ref name="l30"/><ref>Peattie, pp. 54–55; Parshall and Tully, pp. 462–463</ref> The ship carried approximately {{convert|150000|USgal|L}} of [[aviation fuel]] for her embarked aircraft.<ref>Parshall and Tully, p. 477</ref>

As originally completed, ''Akagi'' carried an air group of 28 [[Mitsubishi B1M|Mitsubishi B1M3 torpedo bombers]], 16 [[Nakajima A1N]] fighters and 16 [[Mitsubishi 2MR]] reconnaissance aircraft.<ref name="l9"/>

===Armament and armor===
[[File:Akagi 1929.jpg|thumb|left|upright=0.5|''Akagi'' underway in 1929 with aircraft on the upper flight deck and two 20&nbsp;cm gun turrets on the middle flight deck]]
''Akagi'' was armed with ten 50-[[caliber (artillery)|caliber]] [[20 cm/50 3rd Year Type naval gun|20&nbsp;cm 3rd Year Type No. 1 guns]], six in casemates aft and the rest in two twin-[[gun turret]]s, one on each side of the middle flight deck. They fired {{convert|110|kg|lb|adj=on|sp=us}} projectiles at a rate of 3–6 rounds per minute with a [[muzzle velocity]] of {{convert|870|m/s|ft/s|abbr=on}} at 25°, this provided a maximum range between {{convert|22600|and|24000|m|yd|sp=us}}. The turrets were nominally capable of 70° elevation to provide additional [[Anti-aircraft warfare|anti-aircraft]] fire, but in practice the maximum elevation was only 55°. The slow rate of fire and the fixed 5° loading angle minimized any real anti-aircraft capability.<ref>Campbell, pp. 185–188</ref> This heavy gun armament was provided in case she was surprised by enemy cruisers and forced to give battle, but her large and vulnerable flight deck, hangars, and superstructure made her more of a target in any surface action than a fighting warship. Carrier doctrine was still evolving at this time and the impracticality of carriers engaging in gun duels had not yet been realized.<ref>Peattie, pp. 53, 55</ref>{{refn|The [[United States Navy]] did much the same with the provision of four twin {{convert|8|in|adj=on|0}} gun turrets on their {{sclass|Lexington|aircraft carrier|0}} carriers.<ref>Gardiner and Gray, p. 110</ref>|group=Note}}

The ship carried dedicated anti-aircraft armament of six twin 45-caliber [[12 cm/45 10th Year Type naval gun|12&nbsp;cm 10th Year Type gun]] mounts fitted on [[sponson]]s below the level of the funnels, where they could not fire across the flight deck, three mounts per side.<ref>Lengerer, p. 131</ref> These guns fired {{convert|20.3|kg|lb|adj=on|sp=us}} projectiles at a muzzle velocity of {{convert|825|-|830|m/s|ft/s|abbr=on}}; at 45°, this provided a maximum range of {{convert|16000|m|yd|sp=us}}, and they had a maximum ceiling of {{convert|10000|m|yd|sp=us}} at 75° elevation. Their effective rate of fire was 6–8 rounds per minute.<ref>Campbell, p. 194</ref>

''Akagi''{{'}}s [[Belt armor|waterline armored belt]] was reduced from {{convert|254|to|152|mm|abbr=on|0}} and placed lower on the ship than originally designed. The upper part of her [[Anti-torpedo bulge|torpedo bulge]] was given {{convert|102|mm|abbr=on|0}} of armor. Her [[Deck (ship)|deck armor]] was also reduced from {{convert|96|to|79|mm|in|abbr=on}}.<ref>Lengerer, pp. 128, 130</ref>  The modifications improved the ship's stability by helping compensate for the increased topside weight of the double hangar deck.<ref name="Peattie, p. 54"/>

===Propulsion===
In ''Akagi''{{'s}} predecessor, ''Hōshō'', the hot exhaust gases vented by swivelling funnels posed a danger to the ship, and wind-tunnel testing had not suggested any solutions. ''Akagi'' and ''Kaga'' were given different solutions to evaluate in real-world conditions. ''Akagi'' was given two funnels on the starboard side. The larger, forward funnel was angled 30° below horizontal with its mouth facing the sea, and the smaller one exhausted vertically a little past the edge of the flight deck. The forward funnel was fitted with a water-cooling system to reduce the turbulence caused by hot exhaust gases and a cover that could be raised to allow the exhaust gases to escape if the ship developed a severe list and the mouth of the funnel touched the sea. ''Kaga'' adopted a version of this configuration when she was modernized during the mid-1930s.<ref>Lengerer, pp. 130–131, 137; Peattie, p. 54</ref>

''Akagi'' was completed with four Gihon geared [[steam turbine]] sets, each driving one propeller shaft, that produced a total of {{convert|131000|shp|kW|lk=on}}. Steam for these turbines was provided by nineteen Type B Kampon [[boiler (steam generator)|boiler]]s with a working pressure of {{convert|20|kg/cm2|kPa psi|0|abbr=on|lk=on}}. Some boilers were oil-fired, and the others used a mix of [[fuel oil]] and coal. As a battlecruiser, she was expected to achieve {{convert|28.5|kn|lk=in}}, but the reduction in displacement from {{convert|41200|to|34000|LT}} increased her maximum speed to {{convert|32.5|kn}}, which was reached during her [[sea trial]]s on 17 June 1927. She carried {{convert|3900|LT|t}} of fuel oil and {{convert|2100|LT|t}} of coal that gave her a range of {{convert|8000|nmi|lk=in}} at {{convert|14|kn}}.<ref>Lengerer, pp. 129, 131</ref>

==Early service==
[[File:Akagi Osaka.jpg|thumb|right|upright|A [[stern]] view of ''Akagi'' off [[Osaka]] on 15 October 1934.  On deck are [[Mitsubishi B1M]] and [[Mitsubishi B2M|B2M]] bombers]]
[[File:Akagi Aircraft Carrier & Mitsubishi B1M c1935.jpg|thumb|''Akagi'' & Mitsubishi B1M, c1935]]
''Akagi'' joined the [[Combined Fleet]] in August 1927 and was assigned to the [[First Carrier Division]] upon its formation on 1 April 1928, serving as the division's flagship under Rear Admiral [[Sankichi Takahashi]]. The carrier's early career was uneventful, consisting of various training exercises. From 10 December 1928 to 1 November 1929, the ship was captained by [[Isoroku Yamamoto]], future commander of the Combined Fleet.<ref>Tully; Peattie, pp. 72, 323; Hata and Izawa, p. 20; Lengerer, pp. 130, 170–171; Hoyt, pp. 60–63.</ref>

''Akagi'' was reduced to second-class reserve status on 1 December 1931 in preparation for a short refit in which her arresting gear was replaced and her radio and ventilation systems were overhauled and improved. After completion of the refit, ''Akagi'' became a first-class reserve ship in December 1932. On 25 April 1933, she resumed active service and joined the [[Second Carrier Division]] and participated in that year's Special Fleet Maneuvers.<ref>Peattie, pp. 72, 323; Hata and Izawa, p. 20; Lengerer, pp. 130, 170–171</ref>

At this time, the IJN's carrier doctrine was still in its early stages. ''Akagi'' and the IJN's other carriers were initially given roles as tactical force multipliers supporting the fleet's battleships in the IJN's "[[Kantai Kessen|decisive battle]]" doctrine. In this role, ''Akagi''{{'}}s aircraft were to attack enemy battleships with bombs and torpedoes. Aerial strikes against enemy carriers were later (beginning around 1932–1933) deemed of equal importance, with the goal of establishing [[air superiority]] during the initial stages of battle. The essential component in this strategy was that the Japanese carrier aircraft must be able to strike first with a massed, preemptive aerial attack. In fleet training exercises, the carriers began to operate together in front of or with the main battle line. The new strategy emphasized maximum speed from both the carriers and the aircraft they carried as well as larger aircraft with greater range. Thus, longer flight decks on the carriers were required in order to handle the newer, heavier aircraft which were entering service.<ref>Peattie, pp. 72–76; Stille, p. 13; Goldstein and Dillon, pp. 76–78</ref> As a result, on 15 November 1935 ''Akagi'' was placed in third-class reserve to begin an extensive modernization at [[Sasebo Naval Arsenal]].<ref>Lengerer, pp. 130, 170–171</ref>

==Reconstruction==
''Akagi''{{'}}s modernization involved far less work than that of ''Kaga'', but took three times as long due to financial difficulties related to the [[Great Depression]].<ref>Parshall and Tully, p. 466</ref> The ship's three flight decks were judged too small to handle the larger and heavier aircraft then coming into service.<ref name="Parshall and Tully, p. 7">Parshall and Tully, p. 7</ref> As a result, the middle and lower flight decks were eliminated in favor of two enclosed hangar decks that extended almost the full length of the ship. The upper and middle hangar areas' total space increased to about {{convert|93000|sqft}}; the lower hangar remained the same size.<ref name="pt463"/> The upper flight deck was extended to the bow, increasing its length to {{convert|249.17|m|ftin|sp=us}} and raising aircraft capacity to 86 (61 operational and 25 in storage). A third elevator midships, {{convert|11.8|×|13|m|ftin|sp=us}} in size, was added. Her arrester gear was replaced by a Japanese-designed, hydraulic Type 1 system with 9 wires.<ref name="pt463"/><ref name="l78">Lengerer, pp. 137–138</ref> The modernization added an island superstructure on the port side of the ship, which was an unusual arrangement; the only other carrier to share this feature was a contemporary, the {{ship|Japanese aircraft carrier|Hiryū||2}}. The port side was chosen as an experiment to see if that side was better for flight operations by moving the island away from the ship's exhaust outlets.<ref name="Parshall and Tully, p. 7"/> The new flight deck inclined slightly fore and aft from a point about three-eighths of the way aft.<ref>Watts, pp. 171–172; Jentschura, Jung and Mickel, p. 44</ref>

[[File:Akagi 2.jpg|thumb|left|''Akagi'' at [[Sukumo, Kōchi]], in April 1939 with her new, single deck flight platform and island superstructure]]
''Akagi''{{'}}s speed was already satisfactory and the only changes to her machinery were the replacement of the mixed coal/oil-fired boilers with modern oil-fired units and the improvement of the ventilation arrangements. Although the engine horsepower increased from 131,200 to 133,000, her speed declined slightly from {{convert|32.5|to|31.2|kn|1}} on trials because of the increase in her displacement to {{convert|41300|LT|MT}}. Her bunkerage was increased to {{convert|7500|LT|MT}} of fuel oil which increased her endurance to {{convert|10000|nmi|-1}} at {{convert|16|kn}}. The rear vertical funnel was changed to match the forward funnel and incorporated into the same casing.<ref name="l78"/><ref>Watts, pp. 172–173</ref>

The two 20&nbsp;cm gun turrets on the middle flight deck were removed and 14 twin [[Type 96 25 mm AT/AA Gun|{{convert|25|mm|in|abbr=on|0}} Type 96]] gun mounts were added on sponsons.<ref>Lengerer, p. 139</ref> They fired {{convert|.25|kg|lb|adj=on}} projectiles at a muzzle velocity of {{cvt|900|m/s|ft/s}}; at 50°, this provided a maximum range of {{convert|7500|m|yd|abbr=on}}, and an effective ceiling of {{convert|5500|m|ft|abbr=on}}. The maximum effective rate of fire was only between 110 and 120 rounds per minute due to the frequent need to change the 15-round magazines.<ref>Campbell, p. 200</ref> Six Type 95 directors were fitted to control the new 25&nbsp;mm guns and two new Type 94 anti-aircraft directors replaced the outdated Type 91s. After the modernization, ''Akagi'' carried one Type 89 director for the {{convert|20|cm|abbr=on}} guns; it is uncertain how many were carried before then.<ref name="pt463"/> The ship's crew increased to 2,000 after the reconstruction.<ref>Jentschura, Jung and Mickel, p. 44</ref>

[[File:Akagi AA gun position.jpg|thumb|right|upright=0.6|Port-side anti-aircraft gun sponsons in ''Akagi'', showing their low-mounted position on the hull, which greatly restricted their arc of fire.]]
The ship's anti-aircraft guns were grouped amidships and placed relatively low on the hull. Thus, the guns could not be brought to bear directly forward or aft. Also, the island blocked the forward arcs of the port battery. As a result, the ship was vulnerable to attack by dive bombers. The ship's 12&nbsp;cm 10th Year Type guns were scheduled to be replaced by more modern {{convert|12.7|cm|abbr=on|0}} Type 89 mounts in 1942. The anti-aircraft sponsons were to be raised one deck to allow them some measure of cross-deck fire as was done during ''Kaga''{{'}}s modernization. However, the ship was lost in combat before the upgrade could take place.<ref>Parshall and Tully, p. 138</ref>

Several major weaknesses in ''Akagi''{{'}}s design were not rectified. ''Akagi''{{'}}s aviation fuel tanks were incorporated directly into the structure of the carrier, meaning that shocks to the ship, such as those caused by bomb or shell hits, would be transmitted directly to the tanks, resulting in cracks or leaks. Also, the fully enclosed structure of the new hangar decks made firefighting difficult, at least in part because fuel vapors could accumulate in the hangars. Adding to the danger was the requirement of the Japanese carrier doctrine that aircraft be serviced, fueled, and armed whenever possible on the hangar decks rather than on the flight deck. Furthermore, the carrier's hangar and flight decks carried little armor protection, and there was no redundancy in the ship's fire-extinguishing systems. These weaknesses would later be crucial factors in the loss of the ship.<ref>Peattie, pp. 65, 70, 159; Stille, pp. 15–16; Willmott, p. 415; Parshall and Tully, p. 245</ref>

==Lead-up to World War II==
''Akagi''{{'}}s modernization was completed on 31 August 1938. She was reclassified as a first reserve ship on 15 November, but did not rejoin the First Carrier Division until the following month. In her new configuration, the carrier embarked 12 [[Mitsubishi A5M]] Type 96 "Claude" fighters with four disassembled spares, 19 [[Aichi D1A]] "Susie" dive bombers with five spares, and 35 [[Yokosuka B4Y]] "Jean" horizontal/torpedo bombers with 16 spares.<ref>Hata and Izawa, p. 20</ref> She sailed for southern Chinese waters on 30 January 1939 and supported ground operations there, including attacks on [[Guilin]] and [[Liuzhou]], until 19 February, when she returned to Japan. ''Akagi'' supported operations in central China between 27 March and 2 April 1940. She was reclassified as a special purpose ship (''Tokubetse Ilomokan'') on 15 November 1940, while she was being overhauled.<ref name="l1">Lengerer, p. 171</ref><ref>Hata and Izawa, p. 11</ref>

[[File:Japanese aircraft carrier Akagi 01.jpg|left|thumb|''Akagi'' in the summer of 1941]]
The Japanese experiences off China had helped further develop the IJN's carrier doctrine. One lesson learned in China was the importance of concentration and mass in projecting naval air power ashore. Therefore, in April 1941, the IJN formed the [[1st Air Fleet (Imperial Japanese Navy)|First Air Fleet]], or ''Kido Butai'', to combine all of its fleet carriers under a single command. On 10 April, ''Akagi'' and ''Kaga'' were assigned to the First Carrier Division as part of the new carrier fleet, which also included the Second (with carriers ''Hiryū'' and ''Sōryū''), and [[Fifth Carrier Division|Fifth]] (with ''Shōkaku'' and ''Zuikaku'') carrier divisions. The IJN centered its doctrine on air strikes that combined the air groups of entire carrier divisions, rather than individual carriers. When multiple carrier divisions were operating together, the divisions' air groups were combined. This doctrine of combined, massed, carrier-based air attack groups was the most advanced of its kind in the world. The IJN, however, remained concerned that concentrating all of its carriers together would render them vulnerable to being wiped out all at once by a massive enemy air or surface strike. Thus, the IJN developed a compromise solution in which the fleet carriers would operate closely together within their carrier divisions but the divisions themselves would operate in loose rectangular formations, with approximately {{convert|7000|m|yd|sp=us}} separating each carrier.<ref>Lengerer, p. 171; Parshall and Tully, pp. 82, 86, 137–138, and 416; Peattie, pp. 124–125, 147–53; Tully; Stille, pp. 13–14; Prange, ''At Dawn We Slept'', pp. 101–106</ref>

The Japanese doctrine held that entire carrier air groups should not be launched in a single massed attack. Instead, each carrier would launch a "deckload strike" of all its aircraft that could be spotted at one time on each flight deck. Subsequent attack waves consisted of the next deckload of aircraft. Thus, First Air Fleet air attacks would often consist of at least two massed waves of aircraft. The First Air Fleet was ''not'' considered to be the IJN's primary strategic striking force. The IJN still considered the First Air Fleet an integral component in the Combined Fleet's ''Kantai Kessen'' or "decisive battle" task force centered on battleships.<ref>Parshall and Tully, pp. 86–87</ref><ref>Peattie, p. 152</ref><ref>Goldstein and Dillon, pp. 78–80</ref> ''Akagi'' was designated as the flagship for the First Air Fleet, a role the ship retained until her sinking 14 months later.<ref>Parshall and Tully, pp. 266–267</ref>

Although the concentration of so many fleet carriers into a single unit was a new and revolutionary offensive strategic concept, the First Air Fleet suffered from several defensive deficiencies that gave it, in [[Mark Peattie]]'s words, a {{" '}}[[wikt:glass jaw|glass jaw]]': it could throw a punch but couldn't take one."<ref>Peattie, p. 159</ref> Japanese carrier anti-aircraft guns and associated fire-control systems had several design and configuration deficiencies that limited their effectiveness. Also, the IJN's fleet [[combat air patrol]] (CAP) consisted of too few fighter aircraft and was hampered by an inadequate early warning system, including lack of [[radar]]. In addition, poor radio communications with the fighter aircraft inhibited effective command and control of the CAP. Furthermore, the carriers' escorting warships were not trained or deployed to provide close anti-aircraft support. These deficiencies, combined with the shipboard weaknesses previously detailed, would eventually doom ''Akagi'' and other First Air Fleet carriers.<ref>Parshall and Tully, pp. 85, 136–145; Peattie, pp. 155–159; Stille, pp. 14–15, 50–51</ref>

==World War II==
===Pearl Harbor and subsequent operations===
{{Main|Attack on Pearl Harbor}}
[[File:ChuichiNagumoPDJapan.jpg|thumb|right|First Air Fleet commander Vice Admiral [[Chūichi Nagumo]], for whom ''Akagi'' served as flagship from Pearl Harbor to Midway]]
[[File:Akagi flight deck Hitokappu Bay.jpg|thumb|right|Crewmembers gather on the flight deck of ''Akagi'' at Hitokappu Bay, Kuriles in November 1941 prior to the attack on Pearl Harbor. The other carriers in the background are, from left to right: ''Kaga'', ''Shōkaku'', ''Zuikaku'', ''Hiryū'', and ''Sōryū''.]]
In preparation for the attack, the ship was anchored at [[Ariake Sea|Ariake Bay]], [[Kyushu]] beginning in September 1941 while her aircraft were based at [[Kagoshima]] to train with the other 1st Air Fleet air units for the Pearl Harbor operation. Once preparations and training were completed, ''Akagi'' assembled with the rest of the First Air Fleet at [[Iturup|Hitokappu Bay]] in the [[Kuril Islands]] on 22 November 1941. The ships departed on 26 November 1941 for Hawaii.<ref>Hata, Izawa & Shores, p. 151</ref>

[[File:Akagi Pearl Harbor Second Wave Prep.jpg|thumb|right|A6M2 Zero fighters prepare to launch from ''Akagi'' as part of the second wave during the attack on Pearl Harbor]]
Commanded by Captain [[Kiichi Hasegawa]], ''Akagi'' was Vice Admiral [[Chūichi Nagumo]]'s flagship for the striking force for the [[attack on Pearl Harbor]]<ref name="l1"/> that attempted to cripple the [[United States Pacific Fleet]]. ''Akagi'' and the other five carriers, from a position {{convert|230|nmi}} north of [[Oahu]], launched two waves of aircraft on the morning of 7 December 1941. In the first wave, 27 [[Nakajima B5N]] "Kate" torpedo bombers from ''Akagi'' torpedoed the battleships {{USS|Oklahoma|BB-37|2}}, {{USS|West Virginia|BB-48|2}}, and {{USS|California|BB-44|2}} while 9 of the ship's [[Mitsubishi A6M Zero]]s attacked the air base at [[Hickam Field]]. In the second wave, 18 [[Aichi D3A]] "Val" dive bombers from the carrier targeted the battleships {{USS|Maryland|BB-46|2}} and {{USS|Pennsylvania|BB-38|2}}, the [[light cruiser]] {{USS|Raleigh|CL-7|2}}, the [[destroyer]] {{USS|Shaw|DD-373|2}}, and the [[fleet oiler]] {{USS|Neosho|AO-23|2}} while nine "Zeros" attacked various American airfields. One of the carrier's Zeros was shot down by American anti-aircraft guns during the first wave attack, killing its pilot.<ref>Lengerer, pp. 172, 174–175; Parshall and Tully, p. 131; Werneth, pp. 16–17, 274; Hata and Izawa, p. 21; Evans and Fuchida, p. 54; Prange, "Dec 7", p. 265</ref> In addition to the aircraft which participated in the raid, three of the carrier's fighters were assigned to the CAP. One of the carrier's Zero fighters attacked a [[Boeing B-17 Flying Fortress]] [[heavy bomber]] that had just arrived from the mainland, setting it on fire as it landed at Hickam, killing one of its crew.<ref>Prange, "At Dawn", pp. 199, 258, 266, 365, 390; Prange, "Dec 7", pp. 87, 192, 321; Evans and Fuchida, pp. 42–43</ref>

In January 1942, together with the rest of the First and Fifth Carrier Divisions, ''Akagi'' supported the [[battle of Rabaul (1942)|invasion of Rabaul]] in the [[Bismarck Archipelago]], as the Japanese moved to secure their southern defensive perimeter against attacks from Australia. She provided 20 B5Ns and 9 Zeros for the initial airstrike on [[Rabaul]] on 20 January 1942. The First Carrier Division attacked Allied positions at nearby [[Kavieng]] the following day, of which ''Akagi'' contributed 9 A6M Zeros and 18 D3As. On the 22nd, ''Akagi''{{'}}s D3As and Zeros again attacked Rabaul before returning to [[Chuuk Lagoon|Truk]] on 27 January.<ref>Lengerer, pp. 175–176</ref> The Second Carrier Division, with ''Sōryū'' and ''Hiryū'', had been detached to support the [[Battle of Wake Island|invasion of Wake Island]] on 23 December 1941 and did not reunite with the rest of the carrier mobile striking force until February 1942.<ref>Parshall and Tully, p. 11</ref>

''Akagi'', along with ''Kaga'' and the carrier {{ship|Japanese aircraft carrier|Zuikaku||2}}, sortied in search of American naval forces [[Marshalls–Gilberts raids|raiding]] the [[Marshall Islands]] on 1 February 1942, before being recalled. On 7 February ''Akagi'' and the carriers of the First and Second Carrier Divisions were ordered south to the [[Timor Sea]] where, on 19 February, from a point {{convert|100|nmi|-1}} southeast of the easternmost tip of [[Timor]], they launched [[Bombing of Darwin|air strikes]] against [[Darwin, Northern Territory|Darwin]], Australia, in an attempt to destroy its port and airfield facilities to prevent any interference with the [[Battle of Java (1942)|invasion of Java]]. ''Akagi'' contributed 18 B5Ns, 18 D3As, and 9 Zeros to the attack, which caught the defenders by surprise. Eight ships were sunk, including the American destroyer {{USS|Peary|DD-226|2}}, and fourteen more were damaged. None of the carrier's aircraft were lost in the attack and the attack was effective in preventing Darwin from contributing to the Allied defense of Java. On 1 March, the American oiler {{USS|Pecos|AO-6|2}} was sunk by D3As from ''Sōryū'' and ''Akagi''. Later that same day the American destroyer {{USS|Edsall|DD-219|2}} was attacked and sunk by D3As from ''Akagi'' and ''Sōryū'', in combination with gunfire from two battleships and two heavy cruisers of the escort force. ''Akagi'' and her consorts covered the invasion of [[Java]], although her main contribution appears to have been providing 18 B5Ns and 9 Zeros for the 5 March air strike on [[Cilacap Regency|Tjilatjap]]. This group was very successful, sinking eight ships in the harbor there and none of ''Akagi''{{'}}s aircraft were lost. Most of the Allied forces in the Dutch East Indies surrendered to the Japanese later in March. The ''Kido Butai'' then sailed for [[Staring Bay]] on [[Sulawesi|Celebes Island]] to refuel and recuperate.

===Indian Ocean raid===
{{Main|Indian Ocean raid}}
[[File:Japanese aircraft carrier Akagi Deck.jpg|thumb|left|''Akagi'' leaving Celebes Island for the [[Indian Ocean raid#Attack on Colombo|attack on Colombo]], 26 March 1942. In the background are other carriers and battleships of the carrier striking force. Rolled [[futon]] mattresses have been lashed to the island to provide extra protection from enemy attack.]]
On 26 March, ''Akagi'' set sail for the [[Indian Ocean raid]] with the rest of the ''Kido Butai''. The Japanese intent was to defeat the British [[Eastern Fleet]] and destroy British airpower in the region in order to secure the flank of their [[Japanese conquest of Burma|operations in Burma]].<ref>Lengerer, pp. 176–177, 305–307; Gill, p. 14; Dull, pp. 57–58</ref> On 5 April 1942, ''Akagi'' launched 17 B5Ns and 9 Zeros in an air strike against [[Colombo]], Ceylon, which damaged the port facilities. None of the aircraft were lost and the Zero pilots claimed to have shot down a dozen of the defending British fighters. Later that day, 17 D3As from ''Akagi'' helped to sink the British heavy cruisers {{HMS|Cornwall|56|2}} and {{HMS|Dorsetshire|40|2}}. On 9 April, she attacked [[Trincomalee]] with 18 B5Ns, escorted by 6 Zeros which claimed to have shot down 5 [[Hawker Hurricane]] fighters (only two of which can be confirmed from Allied records) without loss to themselves. Meanwhile, a floatplane from the battleship {{ship|Japanese battleship|Haruna||2}} spotted the small aircraft carrier {{HMS|Hermes|95|2}}, escorted by the Australian destroyer {{HMAS|Vampire|D68|2}}, and every available D3A was launched to attack the ships. ''Akagi'' contributed 17 dive bombers and they helped to sink both ships; they also spotted the [[oil tanker]] [[Royal Fleet Auxiliary|RFA]] ''Athelstone'', escorted by the [[corvette]] {{HMS|Hollyhock|K64|2}}, and sank both without loss. During the day's actions, the carrier narrowly escaped damage when nine British [[Bristol Blenheim]] bombers from Ceylon penetrated the CAP and dropped their bombs from {{convert|11000|ft|m}}, just missing the carrier and the heavy cruiser {{ship|Japanese cruiser|Tone|1937|2}}.<ref>Shores, et al., pp. 395, 403–404, 406, 413, 421–426</ref> Four of the Blenheims were subsequently shot down by CAP fighters and one was shot down by aircraft from the carriers' returning air strike.<ref>Parshall and Tully, pp. 145, 549</ref> After the raid, the carrier mobile striking force returned to Japan to refit and replenish.<ref name="l69">Lengerer, pp. 306, 308–309</ref>

On 19 April 1942, while near Taiwan during the transit to Japan, ''Akagi'', ''Sōryū'', and ''Hiryū'' were sent in pursuit of the American carriers {{USS|Hornet|CV-8|2}} and {{USS|Enterprise|CV-6|2}}, which had launched the [[Doolittle Raid]]. They found only empty ocean, however, for the American carriers had immediately departed the area to return to Hawaii. ''Akagi'' and the other carriers shortly abandoned the chase and dropped anchor at [[Hashirajima]] anchorage on 22 April.<ref>Lengerer, p. 319; Tully; Parshall and Tully, p. 42</ref> On 25 April, Captain [[Taijiro Aoki]] relieved Hasegawa as skipper of the carrier.<ref>Tully</ref>{{Page needed|date=October 2024}}  Having been engaged in constant operations for four and a half months, the ship, along with the other three carriers of the First and Second Carrier Divisions, was hurriedly refitted and replenished in preparation for the Combined Fleet's next major operation, scheduled to begin one month hence.<ref>Parshall and Tully, p. 12</ref> The Fifth Carrier Division, with ''Shōkaku'' and ''Zuikaku'', had been detached in mid-April to support [[Operation Mo]], resulting in the [[Battle of the Coral Sea]]. While at Hashirajima, ''Akagi''{{'}}s air group was based ashore in Kagoshima and conducted flight and weapons training with the other First Air Fleet carrier units.<ref>Parshall and Tully, pp. 10, 88</ref>

===Midway===
{{Main|Battle of Midway}}
Concerned by the US carrier strikes in the Marshall Islands, [[Invasion of Lae-Salamaua|Lae-Salamaua]], and the Doolittle raids, Yamamoto determined to force the US Navy into a showdown to eliminate the American carrier threat. He decided to invade and occupy [[Midway Island]], which he was sure would draw out the American carrier forces to battle.  The Japanese codenamed the Midway invasion Operation ''MI''.<ref>Stille, p. 22</ref>

On 25 May 1942, ''Akagi'' set out with the Combined Fleet's carrier striking force in the company of carriers ''Kaga'', ''Hiryū'', and S''ōryū'', which constituted the First and Second Carrier Divisions, for the attack on Midway Island. Once again, Nagumo flew his flag on ''Akagi''. Because of damage and losses suffered during the Battle of the Coral Sea, the Fifth Carrier Division with carriers ''Shōkaku'' and ''Zuikaku'' were absent from the operation. ''Akagi''{{'}}s aircraft complement consisted of 24 Zeros, 18 D3As, and 18 B5Ns.<ref>Parshall and Tully, pp. 3, 10, 450</ref>{{refn|Six of the Zeros were intended to be stationed on Midway after the invasion and belonged to the 6th Air Group. At least three of these six aircraft were used for combat operations by the carrier's crew during the resulting battle.<ref>Parshall and Tully, pp. 90, 149</ref>|group=Note}}

With the fleet positioned {{convert|250|nmi}} northwest of Midway Island at dawn (04:45 local time) on 4 June 1942, ''Akagi''{{'}}s portion of the 108-plane combined air raid was a strike on the airfield on Eastern Island with 18 dive bombers escorted by nine Zeros. The carrier's B5Ns were armed with torpedoes and kept ready in case enemy ships were discovered during the Midway operation. The only loss during the raid from ''Akagi''{{'}}s air group was one Zero shot down by AA fire and three damaged; four dive bombers were damaged, of which one could not be repaired.<ref>Parshall and Tully, pp. 112, 129, 204; Werneth, p. 20</ref> Unbeknownst to the Japanese, the US Navy had discovered the Japanese ''MI'' plan by breaking the Japanese cipher and had prepared an ambush using its three available carriers, positioned northeast of Midway.<ref>Parshall and Tully, pp. 151, 154; Stille, p. 59</ref>

One of ''Akagi''{{'}}s torpedo bombers was launched to augment the search for any American ships that might be in the area.{{refn|''Akagi''{{'}}s torpedo-bomber scout plane was assigned a search line of 181 degrees from the mobile striking force out to 300 nautical miles.<ref>Parshall and Tully, pp. 107–111</ref>|group=Note}} The carrier contributed three Zeros to the total of 11 assigned to the initial combat air patrol over the four carriers. By 07:00, the carrier had 11 fighters with the CAP which helped to defend the ''Kido Butai'' from the first US attackers from Midway Island at 07:10.<ref name="Parshall and Tully, p. 500">Parshall and Tully, p. 500</ref>

At this time, Nagumo's carriers were attacked by six US Navy [[Grumman TBF Avenger]]s from [[Torpedo Squadron 8]] (VT-8) and four [[United States Army Air Forces]] (USAAF) [[Martin B-26 Marauder|B-26 Marauders]], all carrying torpedoes. The Avengers went after ''Hiryū'' while the Marauders attacked ''Akagi''. The 30 CAP Zeroes in the air at this time, including the 11 from ''Akagi'', immediately attacked the American aircraft, shooting down five of the Avengers and two of the B-26s. One of ''Akagi''{{'}}s Zeroes, however, was shot down by defensive fire from the B-26s. Several of the Marauders dropped their torpedoes, but all either missed or failed to detonate. One B-26, piloted by Lieutenant [[James Muri]], [[Strafing|strafed]] ''Akagi'' after dropping its torpedo, killing two men. Another, seriously damaged by anti-aircraft fire, did not pull out of its run, and instead flew directly at ''Akagi''{{'}}s bridge. The aircraft, either attempting a suicide ramming, or out of control, narrowly missed striking the carrier's [[Bridge (nautical)|bridge]], which could have killed Nagumo and his staff, and crashed into the ocean.<ref>Parshall and Tully, pp. 151–152; Lundstrom, p. 337</ref> This experience may well have contributed to Nagumo's determination to launch another attack on Midway, in direct violation of Yamamoto's order to keep the reserve strike force armed for anti-ship operations.<ref name="Prange, p. 207">Prange, Goldstein and Dillon, pp. 207–212; Parshall and Tully, pp. 149–152; {{cite web |url=http://www.ibiblio.org/hyperwar/USN/USN-CN-Midway/USN-CN-Midway-6.html |title=Office of Naval Intelligence Combat Narrative: "Midway's Attack on the Enemy Carriers" |access-date=28 January 2012}}</ref>

At 07:15, Nagumo ordered the B5Ns on ''Kaga'' and ''Akagi'' rearmed with bombs for another attack on Midway itself. This process was limited by the number of ordnance carts (used to handle the bombs and torpedoes) and ordnance elevators, preventing torpedoes from being struck below until after all the bombs were moved up from their [[Magazine (artillery)|magazine]], assembled, and mounted on the aircraft. This process normally took about an hour and a half; more time would be required to bring the aircraft up to the flight deck, warm up and launch the strike group. Around 07:40, Nagumo reversed his order when he received a message from one of his scout aircraft that American warships had been spotted. Three of ''Akagi''{{'}}s CAP Zeroes landed aboard the carrier at 07:36. At 07:40, her lone scout returned, having sighted nothing.<ref>Parshall and Tully, p. 156–159, 500</ref>{{refn|This recorded return time for ''Akagi''{{'}}s scout aircraft is odd since all the other carrier striking force scout planes had been assigned 600-mile search patterns and would not return for another one and a half to two hours.<ref>Parshall and Tully, p. 550</ref>|group=Note}}

====Sinking====
[[File:Aerial view of the Japanese aircraft carrier Akagi maneuvering on 4 June 1942 (USAF-57576).jpg|thumb|left|''Akagi'' (right, partially obscured by clouds) takes evasive action during an aerial attack by US B-17s shortly after 08:00 on 4 June 1942. The trailing ship at left is probably the carrier's [[plane guard]] destroyer, [[Japanese destroyer Nowaki (1940)|''Nowaki'']]. The photograph was taken from one of the attacking B-17s.<ref>Parshall and Tully, p. 181</ref>]]
At 07:55, the next American strike from Midway arrived in the form of 16 Marine [[Douglas SBD Dauntless|SBD-2 Dauntless]] dive bombers of [[VMSB-241]] under Major [[Lofton R. Henderson]].{{refn|To this day there is much confusion about VMSB-241 at Midway. At that time, the squadron was in transition from the obsolete SB2U Vindicator to the modern SBD-2 Dauntless and flew both aircraft during the battle.<ref>Condon, p. 13</ref>|group=Note}} ''Akagi''{{'}}s three remaining CAP fighters were among the nine still aloft that attacked Henderson's planes, shooting down six of them as they executed a fruitless glide bombing attack on ''Hiryū''.<ref>Parshall and Tully, p. 176</ref> At roughly the same time, the Japanese carriers were attacked by 12 USAAF B-17 Flying Fortresses, bombing from {{convert|20000|ft}}. The high altitude of the bombers gave the Japanese captains enough time to anticipate where the bombs would land and successfully maneuver their ships out of the impact area. Four B-17s attacked ''Akagi'', but missed with all their bombs.<ref>Parshall and Tully, pp. 178, 180</ref>

''Akagi'' reinforced the CAP with launches of three Zeros at 08:08 and four at 08:32.<ref name="p8">Parshall and Tully, p. 508</ref> These fresh Zeros helped defeat the next American air strike from Midway, 11 [[Vought SB2U Vindicator]]s from VMSB-241, which attacked the battleship ''Haruna'' starting around 08:30. Three of the Vindicators were shot down, and ''Haruna'' escaped damage.<ref>Lundstrom, p. 338</ref> Although all the American air strikes had thus far caused negligible damage, they kept the Japanese carrier forces off-balance as Nagumo endeavored to prepare a response to news, received at 08:20, of the sighting of American carrier forces to his northeast.<ref>Parshall and Tully, pp. 183–188</ref>

''Akagi'' began recovering her Midway strike force at 08:37 and finished shortly after 09:00.<ref>Parshall and Tully, pp. 154–155</ref> The landed aircraft were quickly struck below, while the carriers' crews began preparations to spot aircraft for the strike against the American carrier forces. The preparations, however, were interrupted at 09:18 when the first American carrier aircraft to attack were sighted. These consisted of 15 [[Douglas TBD Devastator]] torpedo bombers of VT-8, led by [[John C. Waldron]] from the carrier ''Hornet''. The six airborne ''Akagi'' CAP Zeroes joined the other 15 CAP fighters currently aloft in destroying Waldron's planes. All 15 of the American planes were shot down as they attempted a torpedo attack on ''Soryū'', leaving one [[George H. Gay, Jr.|surviving aviator]] treading water.<ref>Parshall and Tully, pp. 205–209</ref>

Shortly afterwards 14 Devastators from [[Torpedo Squadron 6|VT-6]] from the carrier ''Enterprise'', led by [[Eugene E. Lindsey]], attacked. Lindsey's aircraft tried to sandwich ''Kaga'', but the CAP, reinforced by an additional eight Zeros launched by ''Akagi'' at 09:33 and 09:40, shot down all but four of the Devastators, and ''Kaga'' dodged the torpedoes. Defensive fire from the Devastators shot down one of ''Akagi''{{'}}s Zeros.<ref>Parshall and Tully, pp. 213–214</ref><ref>Stille, p. 62</ref>{{refn|At 10:15, a torpedo bomber had departed the carrier on a scouting mission, but turned back, for unknown reasons, shortly thereafter. The aircraft was recovered by ''Hiryū'' and took part in that carrier's second strike against ''Yorktown''.<ref>Parshall and Tully, pp. 265, 522</ref>|group=Note}}

[[File:VB-6 June 1942.jpg|thumb|right|A group photo of the American dive bomber pilots of VB-6 from ''Enterprise'', three of whom fatally damaged ''Akagi''. Richard Best is sitting in the center of the front row. The other two who attacked ''Akagi'' with Best were Edwin J. Kroeger (standing, eighth from the left) and [[Frederick T. Weber]] (standing, sixth from the right).<ref>Parshall and Tully, p. 239; Cressman, et al., p. 103</ref>]]
Minutes after the torpedo plane attacks, American carrier-based dive bombers arrived over the Japanese carriers almost undetected and began their dives. It was at this time, around 10:20, that in the words of Jonathan Parshall and Anthony Tully, the "Japanese air defenses would finally and catastrophically fail."<ref>Parshall and Tully, p. 219</ref> Twenty-eight dive bombers from ''Enterprise'', led by [[C. Wade McClusky]], began an attack on ''Kaga'', hitting her with at least four bombs. At the last minute, one of McClusky's elements of three bombers from [[VB-6]], led by squadron commander [[Richard Halsey Best|Richard Best]] who deduced ''Kaga'' to be fatally damaged, broke off and dove simultaneously on ''Akagi''. At approximately 10:26, the three bombers hit her with one {{convert|1000|lb|adj=on}} bomb and just missed with two others. The first near-miss landed {{convert|5|-|10|m|abbr=on}} to port, near her island. The third bomb just missed the flight deck and plunged into the water next to the stern. The second bomb, likely dropped by Best, landed at the aft edge of the middle elevator and detonated in the upper hangar. This hit set off explosions among the fully armed and fueled B5N torpedo bombers that were being prepared for an air strike against the American carriers, resulting in an uncontrollable fire.<ref>Parshall and Tully, pp. 239–242</ref>{{refn|American carrier dive bomber doctrine dictated that when two squadrons were presented with two priority targets, in this case ''Kaga'' and ''Akagi'', the first squadron on scene was to attack the more distant target, in this case, ''Akagi''. Apparently unfamiliar with this doctrine, McClusky led his squadron, the first to arrive, at ''Kaga''. Best, following the doctrine, also initially went after ''Kaga''. Only after seeing McClusky's squadron dive past him did Best decide to take his squadron after ''Akagi''. However, most of VB-6 stuck with their original target, so only the lead element took part.<ref>Parshall and Tully, pp. 228, 239</ref> Shortly before the dive bomber attack, ''Akagi'' had recovered five of its CAP Zeros. One Zero relaunched soon afterwards at 10:25, just as Best's bombers were entering their dives on his ship. The other recently landed Zeroes had probably already been taken to the hangar deck. There may have been two or three other Zeroes spotted on the flight deck when the ship was hit by Best's bomb.<ref name="Parshall and Tully, p. 500"/><ref>Werneth, p. 92</ref>|group=Note}}

At 10:29, Aoki ordered the ship's magazines flooded. The forward magazines were promptly flooded, but the aft magazines were not due to valve damage, likely caused by the near miss aft. The ship's main water pump also appears to have been damaged, greatly hindering fire fighting efforts. On the upper hangar deck, at 10:32 damage control teams attempted to control the spreading fires by employing the one-shot {{CO2}} fire-suppression system. Whether the system functioned or not is unclear, but the burning aviation fuel proved impossible to control, and serious fires began to advance deeper into the interior of the ship. At 10:40, additional damage caused by the near-miss aft made itself known when the ship's rudder jammed 30 degrees to starboard during an evasive maneuver.<ref>Parshall and Tully, pp. 254–259; Peattie, p. 159; Werneth, p. 24</ref>

Shortly thereafter, the fires broke through the flight deck and heat and smoke made the ship's bridge unusable. At 10:46, Nagumo transferred his flag to the light cruiser {{ship|Japanese cruiser|Nagara||2}}.{{refn|Nagumo and his staff were forced to evacuate through the forward windows of the bridge by rope. Nagumo's chief of staff, Rear Admiral [[Ryūnosuke Kusaka]], badly sprained both ankles and was burned during the evacuation.<ref>Dull, p. 161; Parshall and Tully, p. 260</ref> At 11:00, seven of ''Akagi''{{'}}s airborne CAP Zeros were recovered by ''Hiryū'' just after she had launched her first strike against the US carriers.<ref>Parshall and Tully, pp. 264, 500–501</ref>|group=Note}} ''Akagi'' stopped dead in the water at 13:50 and her crew, except for Aoki and damage-control personnel, was evacuated. She continued to burn as her crew fought a losing battle against the spreading fires.<ref>Parshall and Tully, pp. 276–278, 299–300</ref>{{refn|Destroyers [[Japanese destroyer Arashi|''Arashi'']] and ''Nowaki'' were directed to stand by the carrier throughout the rest of the day and through the night as she burned uncontrollably. After ''Kaga'' sank, [[Japanese destroyer Hagikaze|''Hagikaze'']] and [[Japanese destroyer Maikaze|''Maikaze'']] joined ''Akagi''{{'}}s escorts.<ref>Parshall and Tully, pp. 267, 339</ref> The carrier's engines, for unknown reasons, restarted around 12:30 and slowly moved the ship, still with a jammed rudder, in a large circle to starboard until they failed again at 13:50. Also, at 13:00, the aft magazines were finally flooded.<ref>Parshall and Tully, pp. 286–288</ref> A large explosion occurred at 15:00, blowing open the bulkhead overhanging the anchor deck.<ref>Parshall and Tully, pp. 309–310</ref>|group=Note}} The damage-control teams and Aoki were evacuated from the still floating ship later that night.<ref>Parshall and Tully, pp. 281, 340–341</ref>{{refn|Aoki refused to abandon ship with the damage control teams at 22:00 and had himself tied to the anchor capstan. Two hours later, the carrier's senior staff, accompanied by Captain Kosaku Ariga, commander of Destroyer Division 4, reboarded the carrier. Ariga, who was senior to Aoki, ordered him to abandon ship. Aoki was the only Japanese fleet carrier commander to survive the battle. He retired from the navy in October 1942 but was recalled to service a year later, and survived the war.<ref>Parshall and Tully, pp. 340–341, 569</ref>|group=Note}}

At 04:50 on 5 June, Yamamoto ordered ''Akagi'' scuttled, saying to his staff, "I was once the captain of ''Akagi'', and it is with heartfelt regret that I must now order that she be sunk."<ref name="pt353">Parshall and Tully, p. 353</ref> Destroyers [[Japanese destroyer Arashi|''Arashi'']], [[Japanese destroyer Hagikaze|''Hagikaze'']], [[Japanese destroyer Maikaze|''Maikaze'']], and ''Nowaki'' each fired one torpedo into the carrier and she sank, bow first, at 05:20 at {{coord|30|30|N|178|40|W|display=inline,title}}. Two hundred and sixty-seven men of the ship's crew were lost, the fewest of any of the Japanese fleet carriers lost in the battle.<ref name="pt353"/>{{refn|Of the ship's fatalities, 115 were engineers, giving that department a 36 per cent casualty rate (the ship had 303 total personnel assigned to engineering), the highest on the carrier. Seven of the carrier's aircrew members were killed, also the fewest of any of the four fleet carriers lost in the battle. Other crewmembers killed included 72 seamen, 68 mechanics, one maintenance man, and five clerks. After returning to Japan, some of the carrier's injured survivors were quarantined in hospitals for almost a year.<ref>Parshall and Tully, pp. 281, 386–387, 417, 476, 561</ref>|group=Note}} The loss of ''Akagi'' and the three other IJN carriers at Midway, comprising two thirds of Japan's total number of fleet carriers and the experienced core of the First Air Fleet, was a crucial strategic defeat for Japan and contributed significantly to Japan's ultimate defeat in the war.<ref>Fuchida and Okumiya, p. 231; Parshall and Tully, pp. 419, 421</ref> In an effort to conceal the defeat, ''Akagi'' was not immediately removed from the Navy's registry of ships, instead being listed as "unmanned" before finally being struck from the registry on 25 September 1942.<ref>Parshall and Tully, p. 388</ref>

==Wreck survey==
On 20 October 2019, the Director of Undersea Operations for [[Vulcan Inc.]] Rob Kraft and [[Naval History and Heritage Command]] historian Frank Thompson aboard {{RV|Petrel}} identified the wreck of ''Akagi'' using high-frequency sonar. Located {{convert|1,300|mi|km}} north west of Pearl Harbor, ''Akagi'' was found at a depth of {{convert|18,011|ft|m}}. It is reported that the wreck is upright, on its keel and is largely intact. Two days before the discovery of ''Akagi'', ''Petrel'' had discovered the wreck of ''Kaga''.<ref>{{Cite news|url=https://www.theguardian.com/world/2019/oct/21/humbling-wreckage-of-japanese-ships-from-battle-of-midway-found-in-pacific|title='Humbling' wreckage of Japanese ships from battle of Midway found in Pacific|last=Beaumont|first=Peter|date=21 October 2019|work=The Guardian|access-date=21 October 2019|language=en-GB|issn=0261-3077}}</ref>

The wreck of ''Akagi'' was visited and photographed by the research vessel [[EV Nautilus]] in September 2023. <ref>{{cite web | url=https://gigazine.net/gsc_news/en/20230912-evnautilus-aircraft-carrier-akagi/ | title=The aircraft carrier Akagi has been seen for the first time in 81 years since it sank in the Battle of Midway | date=12 September 2023 }}</ref> The survey confirmed that the ship was largely intact despite large amounts of damage to the hull, superstructure and flight deck.

==Notes==
{{Reflist|group=Note}}

==Footnotes==
{{reflist|colwidth=25em}}

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==External links==
{{Commons category|Akagi (ship, 1927)|''Akagi''}}
* [https://web.archive.org/web/20100510065717/http://www.history.navy.mil/photos/sh-fornv/japan/japsh-a/akagi2.htm United States Navy photos]
* [http://ww2db.com/ship_spec.php?ship_id=10 WW2DB: Akagi]

{{Amagi class battlecruiser}}
{{WWII Japanese ships}}
{{Pearl Harbor attack}}
{{June 1942 shipwrecks}}
{{featured article}}

{{DEFAULTSORT:Akagi}}
[[Category:Amagi-class battlecruisers]]
[[Category:Ships built by Kure Naval Arsenal]]
[[Category:1925 ships]]
[[Category:Aircraft carriers of the Imperial Japanese Navy]]
[[Category:Second Sino-Japanese War naval ships of Japan]]
[[Category:World War II aircraft carriers of Japan]]
[[Category:Attack on Pearl Harbor]]
[[Category:Ships of the Battle of Midway]]
[[Category:Aircraft carrier fires]]
[[Category:Scuttled vessels]]
[[Category:World War II shipwrecks in the Pacific Ocean]]
[[Category:Maritime incidents in June 1942]]
[[Category:2019 archaeological discoveries]]
[[Category:Shipwreck discoveries by Paul Allen]]