When playing Janken:

グー (Guu) beats チョキ(Choki),

チョキ(Choki) beats パー (Paa)

and パー (Paa) beats グー(Guu).

When it is a draw, it is called あいこ(Aiko).

If you win - you get 50¥ from Sachiko.

Two wins in a row - you get a heart.