320 mm mortar
Encyclopedia
The 320 mm Type 98 mortar (Kyūhachi-shiki-kyūhō = Type98 mortar), was an artillery
weapon used by the Japan
ese military during World War II
, especially during the Battle of Iwo Jima
.
, as well as 24 on Bataan
. The weapon was also used on Okinawa.
. The mortars were mainly operated by the 20th Independent Mortar Battalion.
During the Iwo Jima campaign, many of the 12 to 24 launchers were placed inside the mouths of caves to protect them from American artillery bombardment, requiring the gun crews to live in the caves that housed their guns, like the infantry. Due to the relative difficulty involved in moving such a massive weapon system, their locations usually remained fixed during battles. During the campaign, the object of the gun crews seemed to be mainly to inflict psychological damage
on the American troops instead of killing them.
Artillery
Originally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...
weapon used by the Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
ese military during 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...
, especially during 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...
.
Specifications
The launchers consisted of a steel tube closed at one end by a steel baseplate, resting on a wooden platform. The 675 pounds (306.2 kg), 5 feet (1.5 m), 13 inches (330.2 mm) shells fit around and on top of the tube, instead of being dropped inside, comprising a type of spigot mortar. The range of each shot was adjusted by adding different size powder charges at the base of the round. The barrels could only handle five or six shots apiece before becoming damaged and unusable. When used in large groups, as was often done, it produced a fearsome effect known as "the screaming Jesus" to U.S. Marines. To absorb the massive recoil caused by firing their projectiles, the mortar tubes were almost always placed up against a mound of dirt.Use
During World War II, the Japanese Imperial Army deployed somewhere between 12 and 24 320 mm mortars on Iwo JimaIwo Jima
Iwo Jima, officially , is an island of the Japanese Volcano Islands chain, which lie south of the Ogasawara Islands and together with them form the Ogasawara Archipelago. The island is located south of mainland Tokyo and administered as part of Ogasawara, one of eight villages of Tokyo...
, as well as 24 on Bataan
Bataan
Bataan is a province of the Philippines occupying the whole of the Bataan Peninsula on Luzon. The province is part of the Central Luzon region. The capital of Bataan is Balanga City and it is bordered by the provinces of Zambales and Pampanga to the north...
. The weapon was also used on Okinawa.
Iwo Jima
Japanese officers believed the 320 mm spigot mortar's most effective method of employment was as a psychological weapon, intended to scare American soldiers more than inflict casualties. The 675 pounds (306.2 kg) shells left craters 8 feet (2.4 m) deep and 15 feet (4.6 m) wide, but caused relatively few casualties due to minimal 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...
. The mortars were mainly operated by the 20th Independent Mortar Battalion.
During the Iwo Jima campaign, many of the 12 to 24 launchers were placed inside the mouths of caves to protect them from American artillery bombardment, requiring the gun crews to live in the caves that housed their guns, like the infantry. Due to the relative difficulty involved in moving such a massive weapon system, their locations usually remained fixed during battles. During the campaign, the object of the gun crews seemed to be mainly to inflict psychological damage
Psychological warfare
Psychological warfare , or the basic aspects of modern psychological operations , have been known by many other names or terms, including Psy Ops, Political Warfare, “Hearts and Minds,” and Propaganda...
on the American troops instead of killing them.