This is an improved version of the domestically made battleship main gun mount prototype that was designed by the artillery department of the Kure Naval Arsenal.<br>
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The gun was refined in multiple areas, including improvements to the fire control system and countermeasures against shell explosions. Even though this is a "what-if" equipment, the Kai Nagato-class battleship with this gun mount surpasses the "Big 7" standard of great power at the time tremendously, achieving an excellent balance of offensive and defensive prowess as well as high shelling accuracy.