This is an antique Japanese military sake cup, decorated with what looks like a Nakajima Type 91. The words are "2nd Flying Corps 16th Establishment Commemoration". On the back are the words "Gifu" "Made by Kutani-do". The 2nd Flying Corps is based in Gifu at Kakamigahara Airfield. It was established in 1925, so if it's an annual celebration it should be 1941, although that doesn't explain why we see a Nakajima Type 91 - maybe there's a preceding unit that had a different name/number that it also counts in the number of celebrations.

Condition: Excellent - light fading of the gold

Size: 2" across