Type 91 Grenade

Type 91 Hand Grenade
Type 91 grenade.
Type	Hand grenade/Rifle grenade
Place of origin	Empire of Japan
Service history
In service	1931 - 1945
Used by	Imperial Japanese Army  Imperial Japanese Navy
Wars	Second Sino-Japanese War Soviet-Japanese Border Wars World War II
Production history
Designed	1931
Specifications
Weight	530 grams
Filling	TNT
Filling weight	65 grams
Detonation mechanism	Pyrotechnic delay of 7 to 8 seconds

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 Although superseded as a hand-thrown weapon by the Type 97 by the start of World War II it was still used by units in the Second Sino-Japanese War and by reserve forces, as well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.

The Japanese Army, noting that grenades were short-ranged weapons, began efforts to optimize these weapons for close-in infantry fighting. The first hand-thrown fragmentation grenade was the Type 10. Soon after introduction of the Type 10 grenade to front line combat troops, a number of issues arose. When hand-thrown, instability and inaccuracy of the fuse mechanism made the Type 10 almost as much of a menace to the thrower as to the recipient. Furthermore, the weapon was regarded as undersized, and lacked desired lethality.

The Japanese Army continued to experiment with rifle and hand-thrown grenades between the wars and would adopt a family of fragmentation grenades with almost universal adaptability. Introduced in 1931, the Type 91 fragmentation grenade could be thrown by hand, fired from a cup-type grenade launcher (the Type 100), discharged by a lightweight mortar-like projector (the Type 89 grenade discharger, or knee mortar). or fitted with finned tail-assembly and fired from a spigot-type rifle grenade launcher.