Thank you to Devil and Lyric1 for finding me the info for this skin, which was a request by Devil.
This A6M5 was based at the Japanese Navy's big South West Pacific base of Rabaul in late 1943. At this time the units at Rabaul were organised into nine squadrons and carried the numbers 1-9 on their serial codes, rather than their usual Sentai number. This aircraft from the 9th Squadron carried a diagonal flight leader stripe on the rear fuselage.