Ceramic Grenade
Encyclopedia
The was a “last-ditch” hand grenade
developed by the Imperial Japanese Navy
in the closing stages of World War II
.
, 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. Kiln
s 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.
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.
organizations, such as the Volunteer Fighting Corps, Yokusan Sonendan, and to reservist organizations involved in preparations against the possible invasion of the Japanese home islands by Allied forces
. They were also supplied to front line combat troops in large quantities, and are known to have been employed at the Battle of Iwo Jima
and Battle of Okinawa
.
Hand grenade
A hand grenade is any small bomb that can be thrown by hand. Hand grenades are classified into three categories, explosive grenades, chemical and gas grenades. Explosive grenades are the most commonly used in modern warfare, and are designed to detonate after impact or after a set amount of time...
developed by the Imperial Japanese Navy
Imperial Japanese Navy
The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...
in the closing stages of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
.
History and development
By late 1944 and early 1945, much of the industrial infrastructure of Japan had been destroyed by Allied strategic bombingAir raids on Japan
During World War II the Allied forces conducted many air raids on Japan which caused extensive destruction to the country's cities and killed over 300,000 people. These attacks began with the Doolittle Raid in mid-April 1942, but did not resume until June 1944 when United States Army Air Forces ...
, and there was a growing shortage of raw materials due to Allied naval blockades and submarine warfare
Submarine warfare
Naval warfare is divided into three operational areas: surface warfare, air warfare and underwater warfare. The latter may be subdivided into submarine warfare and anti-submarine warfare as well as mine warfare and mine countermeasures...
. Lacking in metals to mass produce hand grenades in the vast quantities that would be needed against the projected Allied invasion of Japan
Operation Downfall
Operation Downfall was the Allied plan for the invasion of Japan near the end of World War II. The operation was cancelled when Japan surrendered after the atomic bombing of Hiroshima and Nagasaki and the Soviet Union's declaration of war against Japan. The operation had two parts: Operation...
, the Imperial Japanese Navy Technical Bureau developed a design for a cheap, easy-to-make grenade made of ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
or porcelain
Porcelain
Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between and...
materials. Kiln
Kiln
A kiln is a thermally insulated chamber, or oven, in which a controlled temperature regime is produced. Uses include the hardening, burning or drying of materials...
s famous for the production of traditional Japanese pottery
Japanese pottery
Japanese pottery and porcelain , one of the country's oldest art forms, dates back to the Neolithic period...
, such as Arita
Imari porcelain
Imari porcelain is the name for Japanese porcelain wares made in the town of Arita, in the former Hizen Province, northwestern Kyūshū. They were exported to Europe extensively from the port of Imari, Saga between latter half of 17th century and former half of 18 th century, Japanese as well as the...
, Bizen and Seto
Seto, Aichi
is a city located in Aichi, Japan. It is located about 35 minutes from Nagoya by way of the Meitetsu Seto Line.As of April 1, 2011, the city has an estimated population of 133,121, with a household number of 53,253, and the density of 1,192.63 persons per km². The total area is 111.62 km².-...
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 fragmentationFragmentation (weaponry)
Fragmentation is the process by which the casing of an artillery shell, bomb, grenade, etc. is shattered by the detonating high explosive filling. The correct technical terminology for these casing pieces is fragments , although shards or splinters can be used for non-preformed fragments...
body made of terra cotta
Terra cotta
Terracotta, Terra cotta or Terra-cotta is a clay-based unglazed ceramic, although the term can also be applied to glazed ceramics where the fired body is porous and red in color...
or porcelain
Porcelain
Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between and...
materials. The grenade was round-shaped with a bottle neck with a rubber cover and a simple fuse
Fuse (explosives)
In an explosive, pyrotechnic device or military munition, a fuse is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately...
. This detonator
Detonator
A detonator is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the latter two being the most common....
was no more than a blasting cap
Blasting cap
A blasting cap is a small sensitive primary explosive device generally used to detonate a larger, more powerful and less sensitive secondary explosive such as TNT, dynamite, or plastic explosive....
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
Match
A match is a tool for starting a fire under controlled conditions. A typical modern match is made of a small wooden stick or stiff paper. One end is coated with a material that can be ignited by frictional heat generated by striking the match against a suitable surface...
-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.
Combat record
The Type 4 grenades were passed out in large quantities to civil defenseCivil defense
Civil defense, civil defence or civil protection is an effort to protect the citizens of a state from military attack. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation, and recovery...
organizations, such as the Volunteer Fighting Corps, Yokusan Sonendan, and to reservist organizations involved in preparations against the possible invasion of the Japanese home islands by Allied forces
Allies of World War II
The Allies of World War II were the countries that opposed the Axis powers during the Second World War . Former Axis states contributing to the Allied victory are not considered Allied states...
. They were also supplied to front line combat troops in large quantities, and are known to have been employed at the Battle of Iwo Jima
Battle of Iwo Jima
The Battle of Iwo Jima , or Operation Detachment, was a major battle in which the United States fought for and captured the island of Iwo Jima from the Empire of Japan. The U.S...
and Battle of Okinawa
Battle of Okinawa
The Battle of Okinawa, codenamed Operation Iceberg, was fought on the Ryukyu Islands of Okinawa and was the largest amphibious assault in the Pacific War of World War II. The 82-day-long battle lasted from early April until mid-June 1945...
.