This is a a Ki-43-II flown by Capt Masao Miyamaru of the 50 Sentai, an ace who was credited with 8 victories. The yellow lightning bolt indicates the 2nd Chutai, location is Toungoo, Burma, May 1943. This aircraft is illustrated on the cover of Osprey’s Ki-43 ‘Oscar’ Aces of WW2 and profiled inside. The Kanji says “Outstanding Skill”. Mayamaru’s best day was on 31MAR43, when he was credited with downing three RAF Hurricanes over Buthidaung, Burma. He was rotated back to Japan where he served as an instructor at the Akeno Army Flying school. He was deployed for the defense of the Philippines with the 200th Sentai, where he was killed in October 1944.