 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.This weapon was featured in the American bladesmthing competition, Forged in Fire (TV series)'s season 1 episode 8.It is believed that the predecessor of the kalis, the keris, first appeared in the 13th century, originally from the island of Java in Indonesia.