A bit of whimsy...perhaps pre-war, but probably post-GHQ era, as there's no Occupied Japan anywhere on the carton (which is stapled together, rather than glued). It's made of plated brass, and 'tho the carton is pretty ratty, the cup and its cutter show no use...they've lived in the box, which has been handled...a lot! I've done some searching, but so far No Joy. It seems that the instructions (Pic 6) are in more than one script for domestic illumination. Thanks for lookin'!
Approximate translation. How to use: Remove the shell from the egg and put it in the cup. 1. Cut as shown, a very beautiful flower can be cut.
The photo in the post does not have the cutter in the correct position. It should line-up to match the shape of the points on the cup. The cutter slides only to the center of the egg.