Jankenpon

Jankenpon (じゃんけんぽん) or just "janken" is the Japanese name for the rock-paper-scissors game. You will often seen it played in anime and manga to make decisions.

It isn't a directly translatable Japanese phrase, supposedly a corruption of the Chinese pronunciation of "両拳碰, which is pronounced in Cantonese "loeng kyun pung".　碰 in Chinese means "to collide" or "to clash", so the full phrase means "two fists collide".

While playing the game, players say "Jan-ken" showing their fist for first 2 syllables and then show their play when they say "pon". There are other rituals related to the game, but those are the basics.

Japanese equivalents to rock, paper, scissors:
 * Rock is called "Guu" (ぐう?)
 * Paper is called "Paa" (ぱあ?)
 * Scissors is called "Choki" (ちょき?)