Vessels made by several potteries, finishing by Asano Carlit
Produced
1944–1945
Specifications
Mass
ca. 455 g (1.003 lb)
Height
ca. 102 mm (4.0 in)
Diameter
various, ca. 76 mm (3.0 in)
Filling
Type 88 explosive
Filling weight
ca. 100 g (0.22 lb)
Detonation mechanism
Fuse delay of 4 to 5 seconds
The Type 4 grenade or ceramic grenade (四式陶製手榴弾, Yon-shiki tōsei teryūdan) was a "last-ditch" hand grenade developed by the Imperial Japanese Navy in the closing stages of World War II.
History and development
By late 1944 and early 1945, much of the industrial infrastructure of Japan had been destroyed by Allied strategic bombing, and there was a growing shortage of raw materials due to Allied naval blockades and submarine warfare. Lacking in metals to mass-produce hand grenades in the vast quantities that would be needed against the projected Allied invasion of Japan, the Imperial Japanese Navy Technical Bureau developed a design for a cheap, easy-to-make grenade made of ceramic or porcelain materials. Kilns famous for the production of traditional Japanese pottery, such as Arita, Bizen and Seto were pressed into service to manufacture these relatively crude weapons. There were a tremendous number of variants on shape, size and color, because the design depended on each kiln.
Design
The Type 4 grenade had a fragmentation body made of terra cotta or porcelain materials. The grenade was round-shaped with a bottle neck with a rubber cover and a simple fuse. This detonator was no more than a blasting cap crimped on to a five-second length of fuse. The other end of the fuse, which was outside the rubber plug, was covered with a match-head composition. A slip-on rubber cap covered the whole neck, and fuse. A small, loose wooden block with an abrasive composition on one side was contained in the rubber fuse cover.[1]
US Department of War (1994). Handbook on Japanese Military Forces, TM-E 30-480 (1945) (reprint ed.). Louisiana State University Press. ISBN0-8071-2013-8.
Japanese Explosive Ordnance, TM 9-1985-4. Departments of the Army and the Air Force. 1953. ASINB000H7NCDS. OCLC506057724.
