Neat. The deck should open up because it's a salt cellar. The holes in the bow are for sprinkling the salt. It would have had a partner with more bow holes for sprinkling pepper.
If you check on eBay, similar vintage items seem to have asking prices in the region of $80 for a solo one without its partner. Rather more than double that for a matching pair. I think it could be from around the 1920s... just scraping in as antique rather than vintage.
There was an Ordinance in Japan requiring the purity of silver to be marked with decimal numbers from around 1928, but some makers were already using marks such as .950 from around 1912. There were almost no luxury silver pieces made in the Japanese Empire for its populace after 1938 when the Empire put its economy on a war footing, and that didn't resume until well after the war ended.