Featured Japanese Daruma Sake Cup with Floating Eyes

I may have known what this gimmicky feature was called, but cannot recall now. Those eyes are voids in the bottom, wherein reside 2 wee black 'things' that move when liquid fills the cup.
The circular mark in the back is unevenly stamped, so is incomplete; it may offer some clues if y'all can read any of it. I think it's post-war, but that's a guess. Any of your observations will be welcome, an' valuable. Thanks for lookin'!

 

thats way cool whit, what do his eyes do? (is it the same thing that the ladies do when i give um my best chat up lines ?)

are you sure thats stamped ?, looks painted from here

 

i like him for being older as well

 

Up close it's pretty plainly stamped, but it's overglaze an' the strokes have depth...so I cannot rule out painted; you may be right.

I'll fill it with spirits, an' record the results (on the cup, not on the unfortunate fellow who must consume those evil spirits to prevent waste).

 

just make sure the shots in focus

 

Dial it down and blink every now n' then !

 

When liquid (I used plain ol' water) fills the cup, those eyes move, seeming to follow you as the cup is tilted this way an' that.
I think the secret is that the material the wee beads are made of is carefully chosen to be of neutral buoyancy; they don't float, nor do they sink, in their voids behind the eye-holes. bicbw...
I would sure like to know what the feature, or the cup that displays it, is properly called. Help me out, here, if you can.

 

yeah i would like to know as well whit (never seen anything like it)

its got so much going for it though, he's got a cool animation character look

and the fact that its got a fun gadget type as well makes it twice as interesting

 

perhaps sir mikey wouldn't mind having a look

@916Bulldogs123

 

I haven't seen it before either. Very neat piece.
The Japanese made some interesting items for sure. I have a few whistling bird chirping sake bottles. But nothing like this.
Mikey

 

Cool! Something most of us haven't seen before. I haven't. A tad creepy but would make you laugh rather than scream, LOL.