This is a very rare, antique Japanese wooden tobacco box decorated with the words "Showa 13th Year (1938) Autumn, China Incident Participation Commemoration, Destroyer Shiratsuyu". Shiratsuyu was the lead ship of its namesake class of destroyers, then one of the newest in 1938, having been commissioned only two years earlier. It participated in the Battle of Coral Sea and a number of naval actions after, and eventually sank after a collision with an oil tanker. 

It's quite rare to find named ship items of any sort - especially ones pertaining to specific military actions. The Japanese navy participated in China Incident mostly through coastal bombardment and helping the landing around Shanghai. Shiratsuyu was probably part of that task force. The box is made of very heavy wood - Chinese Wistaria, probably, and given the style it is possible that the piece was commissioned in China after the Japanese occupation. 

Condition: Some minor surface wear. Please see pictures

Size: 6" x 4.5" x 3"