This was the standard Japanese light AA of the war, being mounted aboard practically everything that floated. It was an adaptation of a French Hotchkiss design. It was also a very mediocre weapon, being hampered by slow training and elevating speeds (even in power-operated triple mounts), excessive vibration and muzzle flash, and the fact that the ammunition feed was via a 15-round fixed magazine which necessitated ceasing fire every time the ammo had to be changed. All in all, it was more comparable to the U.S. 20mm Oerlikon, and was vastly inferior to the U.S. 40mm Bofors in every respect except rate of fire (and only barely in that respect: the Bofors could put out a sustained 120 round/minute because of its constant-fire top-fed ammo clip design; whereas the 25mm's frequent ammo box changes lowered its nominal rate of fire to only half of its theoretical maximum of 260 rounds / minute). This stunning lack of an adequate medium automatic AA weapon, coupled with inferior fire control, proved to have dire consequences for Japanese surface units as the war progressed.
