Due to the focus on shipborne air forces, the Empire's Navy had not considered developing twin-engine heavy-duty fighters before the war.
Even after the outbreak of the war, the Navy only thought about extending the range by increasing the internal fuel and did not consider adding an extra engine to the fighters.
There was only one reason: the heavy fighters were too large to be accommodated on aircraft carriers.
Strictly speaking, it was impossible to operate them on aircraft carriers.
