Almost every child that has grown up in Japan has seen a kendama, a wooden traditional Japanese toy consisting of a ken (sword) and tama (ball) connected by a length of string.

The ken has three cups and a spike that fits into a hole that has been drilled through the center of the ball. Using their knees, kendama players bounce as they pull the ball upward so that it may either be caught in one of the cups or land on the spike. All in all, it used to be a very simple and straightforward game.

Not anymore.