@kronix
Explanation can be pretty good, but would someone still accept it that quickly?
@Kaarme
Well firstly, they had nowhere near the manufacturing capabilities to give every single soldier a sword, unless they would've been cheap & quick massproduced ones.
Secondly, a major part of the defeat of Japan in the pacific theatre of war, was that the Allies sunk a lot of their shipping, which included lots of equipment and thousands upon thousands of troops.
Thirdly, Banzai Charges only worked in the first parts of the war, later on, they had minimal if any positive effect for them.
So sure, they could've provided more swords to their troops, but they would've achieved even less in most cases and possibly slightly more in a few, but at way heavier losses. And the only way they could've maximised the use of katanas, was to only fight on their mainland, which would've allowed them maximum amounts of troops able to fight at any one time, and quick replenishments of troops and materiel up until a certain point. But ... they would've still lost, and the destruction on the mainland would've been way worse.