Variants
Y-20   Prototype version
P1Y1   Initial production version
P1Y1a   20mm gun in nose, 13mm gun dorsal
P1Y1b   20mm gun in nose, twin 13mm guns dorsal
P1Y1c   13mm gun in nose, twin 13mm guns dorsal
P1Y1-S Byakko  Night-fighter variant, armed with two pairs of obliquely mounted 20mm cannon-one pair forward and one pair aft of the cockpit
P1Y2-S Kyokko   Night-Fighter variant New engine, nose gun was eliminated, and a brace of 20mm cannon firing forwards and upwards installed in the fuselage amidships (96 built)
P1Y2   Day bombers, P1Y1-S conversion with angled cannon removed, flexible nose cannon restored, and operated as day bombers
P1Y2a   20mm gun in nose, 13mm gun dorsal
P1Y2b   20mm gun in nose, twin 13mm guns dorsal
P1Y2c   13mm gun in nose, twin 13mm guns dorsal
P1Y3   Intended as mother ship for Ohka Model 21 or Ohka Model 22 flying bombs, enlarged fuselage, extended wingspan  and more powerful engines
P1Y4, P1Y5, P1Y6   All left on drawing board