This Nambu Pistol is an example of a semi-automatic pistol produced in Japan and used during the Second World War. This pistol appears to be a Type 14 based on the oblong trigger guard.
The pistol was reported to have been picked up on Luzon, Philippines. Luzon, an island of the Philippines captured by the Imperial Japanese forces in 1942, was the site of a decisive victory for the Allied forces in 1945. This land battle is noted for the high number of casualties received by both Japanese and U.S. forces: “The Battle for Luzon cost Japan some 205,535 killed and 9,050 captured. U.S. losses were 8,310 killed and 29,560 wounded” (http://www.pbs.org/thewar/detail_5226.htm).