 "47 Chutai", after it was transferred to air defense roles in Japan, was expanded to become "47 Sentai".The Ki-44-II "Otsu" (also known as the Ki-44-IIb) could be armed with a Ho-301 40 mm autocannon.While this was a relatively high-caliber weapon, it used caseless ammunition with a low muzzle velocity and short range, which was effective only in close attacks.