In 1966, Yamauchi was observing a hanafuda factory. He noticed an extending arm, which was made by one of their maintenance engineers, Gunpei Yokoi, for his own amusement. Yamauchi ordered Yokoi to develop it as a proper product for the Christmas rush. Released as the "Ultra Hand", it would become one of Nintendo's earliest toy blockbusters, selling over a million units. Seeing that Yokoi had promise, Yamauchi pulled him off assembly line work. Yokoi was soon moved from maintenance duty to product development.