If our member @Yang Hao sees this, I’m sure he will be able to say if this is complete rubbish… but Google gives an approximate translation along the lines of “jewel/gem/something precious from the East” and says it’s a famous type of rice used to make saké with a unique and rich flavour. If that’s correct, I would guess it held a miniature/sampler of the Japanese wine, possibly from a souvenir/gift set.