Japan began to depart from the Six-Six Fleet's common twelve-inch and six-inch pattern with the Katori class, which added four single ten-inch guns. The Satsuma class went further with six twin ten-inch mountings and a 20-knot speed. The trade is questionable because the ten-inch weapon's rate of fire was much closer to a twelve-inch gun than to faster 9.2-inch or eight-inch weapons. Its magazines and internal support also consumed nearly as much ship space and infrastructure as a twelve-inch battery. The result approached a larger Lord Nelson-style semi-dreadnought without delivering the hitting power of a uniform twelve-inch armament.
Notable Point · 50:50-52:15
The ten-inch-gun compromise after Asahi
Katori and Satsuma moved toward semi-dreadnought layouts, but their ten-inch batteries demanded nearly battleship-scale support without twelve-inch hitting power.