Japanese currency

Japan's first formal currency system was the Kōchōsen (Japanese: 皇朝銭, "Imperial currency"). It was exemplified by the adoption of Japan's first official coin type, the Wadōkaichin. It was first minted in 708 on order of Empress Gemmei, Japan's 43rd Imperial ruler."Wadōkaichin" is the reading of the four characters printed on the coin, and is thought to be composed of the era name Wadō (和銅, "Japanese copper"), which could alternatively mean "happiness", and "Kaichin", thought to be related to "Currency". The pronunciation of "Kaichin" also sounds similar to "happiness" in Chinese "开心". This coinage was inspired by the Tang coinage (唐銭) named Kaigentsūhō (Chinese: 開元通宝, Kai Yuan Tong Bao), first minted in Chang'an in 621. The Wadokaichin had the same specifications as the Chinese coin, with a diameter of 2.4 cm and a weight of 3.75g.

Currency reform (760)

The Wadōkaichin soon became debased, as the government rapidly issued coins with progressively lesser metallic content, and local imitations thrived. In 760, a reform was put in place, in which a new copper coin called Mannentsūhō (万年通寶) was worth 10 times the value of the former Wadōkaichin, with also a new silver coin named Taiheigenbō (大平元寶) with a value of 10 copper coins, as well as a new gold coin named Kaikishōhō (開基勝寶) with a value of 10 silver coins.