Kalis
A kalis is a type of double-edged Filipino sword, often with a "wavy" section, similar to a keris. Just like the keris, the Kalis's double-edged blade can be used for both cutting and thrusting; except that the Kalis is much larger than most Kerises, making it a sword rather than a dagger.
The wavy portion of the kalis is said to be meant to facilitate easier slashing in battle - since a straight edge tends to get stuck in the opponent's bones, the wavy portion allows the kalis' bearer to more easily pull the weapon out of his opponent's body.
History
It is believed that the predecessor of the keris first appeared in the 13th century, originally from the island of Java in Indonesia. In Indonesia, versions of the kris can be found in Kalimantan and Sulawesi, where is it known as Sundang, Sondang or Sulu Keris. From there the kalis migrated to the Philippines. Countries in which the kalis is considered to be one of the main weapons including Malaysia and some other countries in Southeast Asia.