The Video Game Critic

In many early NES games, especially CAPCOM ones (Ghosts N Goblins, Commando, 1942...) there is a power-up or one-up item that looks like a pinwheel in a circle called the "YASHICHI" -
it is very common.

Anyone know what it represents in Japan? I've never found out.
Is it a good luck token, weapon or what?