− | ''?? | + | ''This is an improved version of No.3 Japan's 20.3 cm main gun for heavy cruisers.<br>It is a "what if" version of the 55 caliber heavy cruiser main gun that has been further matured, with an improved 6 m rangefinder, an increased firing speed, an improved ammunition structure and explosion prevention, and further ameliorations given to cooperate with radars. |