Type 91 Grenade

Infobox Weapon
name=Type 91 Hand Grenade


caption= Type 91 grenade.
origin=flag|Empire of Japan
type=Hand grenade/Rifle grenade
is_explosive=yes
service=1931 - 1945
used_by= navy|Empire of Japan
wars=Second Sino-Japanese War Soviet-Japanese Border Wars World War II
designer=
design_date=1931
manufacturer=
production_date=
number=
variants=
weight= 530 grams
length=
part_length=
crew=
diameter=
filling=TNT
filling_weight=65 grams
detonation=Pyrotechnic delay of 7 to 8seconds
yield=The nihongo|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 Although obsolete and superseded by the Type 97 by the start of World War II it was still used by units in the Second Sino-Japanese War and by reserve forces, as well as the Japanese Navy's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. [ [http://www3.plala.or.jp/takihome/grenade.htm] Taki’s Imperial Japanese Army page]

History and development

Soon after introduction of the Type 10 hand grenade to front line combat troops, a number of issues arose. 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 in the desired lethality. In 1931, the Army Technical Bureau developed an improved version intended to address some of these issues.

Design

The design of the Type 91 grenade was almost identical to the earlier Type 10. The main difference was the Type 91’s dome top as opposed to the Type 10's serrated top. As with the Type 10, a threaded socket in the bottom of the body allowed for the attachment of an auxiliary propellant canister for use in a grenade launcher, or a finned tail assembly for use as a rifle grenade. The fuse was a percussion-activated delay type, initiated by pulling out a safety pin and striking the top of the cap, which gave a 7-8 second delay. When used as a rifle grenade with a tail assembly added or mortar round with a base containing a primer and propelling charge, the fuse activated automatically, as the plunger was pushed in by the force of the launch. The issue with the highly variable and inaccurate fuse timing remained unresolved. [ [http://www.inert-ord.net/jap02h/grenades/t99/index.html Japanese World War II Ordinance] ] As with the Type 10, the Type 91 could be used with the either the Type 10 or Type 89 Grenade Discharger. It can be used as a booby trap by removing the safety pin and setting under a floor board or chair. [ [http://www.inert-ord.net/jap02h/grenades/t91/index.html Details of internal construction] ]

Variants

When the Type 97 with its shortened delay came into production and was being delivered to front line combat units, the Japanese Army still had considerable stock of the older Type 91s. Many of these older grenades were modified by shortening the fuse to a four to five second delay, drilling out the base, and welding small extensions on the body, so that it could not fit into the Type 10 Grenade Discharger, and painting the bottom white. The resulting modified Type 91 was visually almost identical to the Type 97 except for its white base. [ [http://www.inert-ord.net/jap02h/grenades/t99/index.html Details of internal construction] ]

Combat record

The Type 91 (modified) was issued as a standard hand grenade to Japanese infantrymen in the Second Sino-Japanese War and throughout the various campaigns of World War II. [Rottman, Japanese Infantryman 1937-1945]

References

*
*
*cite book|author= Departments of the Army and the Air Force|title=Japanese Explosive Ordnance, TM 9-1985-4|publisher=|year=1953|id= ASIN B000H7NCDS

External links

* [http://www.inert-ord.net/jap02h/grenades/t91/index.html Japanese World War II Ordinance]
* [http://www3.plala.or.jp/takihome/grenade.htm Taki’s Imperial Japanese Army page]
* [http://www.ibiblio.org/hyperwar/Japan/IJA/HB/HB-9.html#III US Technical Manual E 30-480]

Notes