Very Rare Antique Japanese Whistling Military Sake Cup
This is a very rare antique Japanese military sake cup that also has a whistle. Whistling cups are a unique type of sake cup that has this little extra hole attached to the side of the cup. When you drink from it and you suck air at the same time air flows through the hole at the bottom and sounds a whistle. The cup is decorated on the inside with a star and the words "Leaving the service commemoration", and the exterior has a blue cherry blossom pattern. While whistling cups are not all that rare (they're certainly uncommon) most of the ones I encounter are non-military.
Size: 2" across