The Type 91 Hand Grenade (九一式手榴弾, Kyūichi-shiki Teryūdan) was an improved version of the Type 10 fragmentation hand grenade/rifle grenade of the Imperial Japanese Army. Although superseded as a hand-thrown weapon by the Type 97 by the start of World War II it was still used by units in the Second Sino-Japanese War and by reserve forces, as well as the Japanese Navy's Special Naval Landing Forces.