英語ノート
EigoNoto.com

In Japan, Janken is a game of inexplicable popularity with both young and old.  Often this popularity alone can turn an otherwise hum-drum activity into one that brings smiles to the students' faces and encouragement to continue.
But also very importantly, in conversation classes Janken unequivocally decides the order of speaking- who will go first, and who will follow. These two points have made Janken a very important asset in my bag of teaching tricks.
If you use points in your classes as a motivation tool (see the EigoNoto.com Australia Points Map), giving large amounts of points for winning at Janken is a way to help lower-level students, who may not score many points in ability-centered activities, to earn as many points as their higher-ability peers.