In game its called Ki-61-II Otsu Kai or how i like to call it, Ki-61-II Kai Otsu (or Ki-61-II KAIb)
Doesnt matter which of the 3 you use, they are all correct.
However the aircraft in game is definitly not the Otsu version…
Lets take a look at the Ki-61’s…
Ki-61-I’s (all) have 1 thing in common. Ha-40 engine (1160hp)
Ki-61-II’s (all) have 1 thing in common. Ha-140 engine (1500hp)
Ki-100-I’s (all) have 1 thing in common. Ha-112-II engine (1500hp)
Ki-100-II has Ha-112-II Ru engine (1500hp)
But lets focus on the Ki-61-II’s
Ki-61-II was prototype version with bigger wings but since the wings turned out to be structurally weak, the design was rejected and remained a prototype version.
Ki-61-II KAI version went back to using the original wing used by the Ki-61-I’s (Tony 1’s)
Ki-61-II Kai Ko has the standard cockpit
Ki-61-II Kai Otsu had the bubble canopy cockpit
Ki-100-I Ko has the standard cockpit
Ki-100-I Otsu has the bubble canopy cockpit