A beautiful and rare art light bulb made in Japan in the 1950s by the Kokka-Hana-Denkyu Company.
It Works! I plugged it into a normal lamp to test and it screwed in just fine. The base glass is cobalt-blue tinted, and it appears that the top is also blue tinted instead of clear. The last photo shows that the main filament works as well.
There's a little bit of pitting on the outside glass and a couple of air bubbles.