Kendama is a popular cup-and-ball toy in Japan. It has a hammer-like object connected to a ball by a string. It seems like a simple toy, but it takes practice to master catching and balancing the "Tama" (ball) to the Ken (handle), and vise versa. The ends of the handle are cupped so it would fit the ball when catched. The ball also has a hole that suits to the pin atop the hammer. It's now getting popular among Americans nowadays.