DISK, DISPLAYED SYMBOL IDENTIFIER OF MECHANICAL SLOT MACHINE, AND MECHANICAL SLOT MACHINE

A disk for identifying individual symbols on a reel displayed in a symbol display region of a mechanical slot machine, the disk being concentric with the rotational axis of the reel and rotatable along with the reel, the disk surface being provided with a plurality of convex members protruding radially around the rotational axis, and the plurality of convex members each having at the top a detection surface whose distance from the rotational axis is within a unique range.