This woulda been a mean ground pounder
MANSYU
KI-98
Whether the Saab 21 of nearly identical layout was copied or not in 1943, the Ki-98 was very similar. It was born as a ground attack aircraft though several other planes already filled that role, which was not a big priority in Japan in any case. Of course Japan later expected an Allied landing on its shores so that is why ground attack craft were reconsidered.
Much slower planes like the Ki-45 and Ki-102 in ground attack were effective but suffered at the hands of Allied fighters mostly driving them to night usage to survive much like the twin-engine Bf 110 in Germany. Ground attack can't be carried out at night so a higher speed day fighter was called for.
The Ki-98 was to have a span of 37 feet and a length of 37.3 feet with a loaded weight of 9,921 lbs. Performance was to come from a turbo-supercharged 2,200 HP Mitsubishi Ha. 211ru, 18-cylinder radial turning a four-blade pusher propeller. It looked not unlike the aforementioned J4M1. At least it was proposing a powerful enough engine. The twin-boom met the wing at slightly different angles and the nose of the Ki-98 was more pointed.
In that nose were to reside a pair of 20 mm Ho-5s and one 37 mm Ho-203 cannon. That nose would slice through the air at 454 MPH up at 32,810 feet with speed unknown on the deck. Ceiling was to be 39,370 feet and the plane would have a range of 621 miles. Underwing ordnance loading was not discussed though it certainly would have lent itself to any mixture of weapons.
Unorthodox airframes were never in favor with the Imperial Army or Navy procurement boards. A late war super plane, the Tachikawa Ki-94 I, was of this configuration and rejection resulted in a complete redesign to the conventionally shaped Ki-94 II. The Ki-98 did just get to the commencement of construction of a prototype though at the end of the war.
The Ki 98 was a solid design and would have offered superior prop-engine performance.