Kawachi appeared to carry a uniform all-12-inch main battery, but the fore-and-aft twins used 50-caliber guns while the eight wing-turret weapons were 45-caliber pieces. The two types would not share identical ballistic performance, complicating the usual all-big-gun definition of a dreadnought. That limitation did not make the class harmless. About 25,000 shaft horsepower and turbine machinery supported a 21-knot speed on a normal displacement approaching 22,000 tons. The ships still had useful protection and enough heavy firepower that an opponent could not safely ignore them. Caliber alone did not determine whether a battery behaved as a genuinely uniform system.
Notable Point · 15:05-16:38
Kawachi's mixed 12-inch battery complicates the dreadnought label
Japan's Kawachi class had 12-inch guns throughout, but different barrel lengths undermined the uniform ballistic performance expected of an all-big-gun battleship.