[CaptainCrunch]

It didn't as much regress as the IJA held incredible sway over the whole Imperial Military Machine, and even with the early successes they still had the fortress mentality at sea. They envisioned that the Navy should be focused on drawing the American Navy into a final confrontation after Pearl Harbor where a massive chunk of the American Battleship fleet was destroyed or disabled, and they didn't understand that technically a Battleship versus a attack from the air was a losing proposition.

Pearl Harbor was a success because Yamamoto was able to sell a vision of Carriers as a front line weapon, however Midway showed the failure of the Battleship as they couldn't keep up to the Carriers and their fire power was excluded from the Battle.

There were lots of technical issues with a battleship. Its best range of fire was horizontally, it was weak in terms of its anti-air defense, and it had thin armor plating on its fore and aft decks which lead right down to the bunkers and magazines.

At its best, the Battleship was a purely offensive weapon, a Fleet death star to effect, it couldn't function well as an escort or protection for a Carrier Battle group, and actually needed protection of its own against Air Threats.

There were two major failures at Midway. One was scouting, the Japanese scout plan was piss poor and it allowed their fleet to be out maneuvered and they lost the battle of time. The Americans with its improved scouting were able to find the Japanese first and this was crucial.

The other major failure was patience. They pretty much should have arrived with the Battleships and used them as a maneuver force to threaten the American Carrier Groups to keep the initiative and force the American's to split their air forces.