The was a

self-propelled gun Self-propelled artillery (also called locomotive artillery) is artillery equipped with its own propulsion system to move toward its firing position. Within the terminology are the self-propelled gun, self-propelled howitzer, self-propelled mo ...

developed by the

Imperial Japanese Army The was the official ground-based armed force of the Empire of Japan from 1868 to 1945. It was controlled by the Imperial Japanese Army General Staff Office and the Ministry of the Army, both of which were nominally subordinate to the Emperor o ...

for use in

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

History and design

The Type 4 Ha-To was conceived as a mobile fire support platform in late 1943. It made use of the already existing Type 3 300 mm heavy mortar mounted on a modified chassis that was based on the one used for the

Type 4 Chi-To The ("Imperial Year 2604 Medium Tank Model 7") was one of several medium tanks developed by the Imperial Japanese Army towards the end of World War II. While by far the most advanced Japanese wartime tank to reach production, industrial and mate ...

medium tank A medium tank is a classification of tanks, particularly prevalent during World War II which represented a compromise between the mobility oriented light tanks and the armour and armament oriented heavy tanks. A medium tank's classification is ...

and on the Type 4 Chi-So armored medium tracked carrier.Taki's Imperial Japanese Army Page: Type 4 30cm SP Heavy Mortar Carrier "Ha-To"
/ref> The armor was "thinner" than the Chi-To and the engine compartment was moved to the front. The mortar had a range of 3,000 m (1.9 mi) and launched a 170 kg (374 lb)

projectile A projectile is an object that is propelled by the application of an external force and then moves freely under the influence of gravity and air resistance. Although any objects in motion through space are projectiles, they are commonly found in ...

. The gun itself weighed close to 1.5 tons, and to keep the

center of gravity In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weight function, weighted relative position (vector), position of the distributed mass sums to zero. Thi ...

from shifting and tipping the vehicle over, it could not be elevated more than 50 degrees. The first prototype was completed in late 1944 and taken to the

Imperial Japanese Army Academy The was the principal officer's training school for the Imperial Japanese Army. The programme consisted of a junior course for graduates of local army cadet schools and for those who had completed four years of middle school, and a senior course f ...

for testing. Although testing indicated that it would be an effective weapon, it was expensive to produce, and the Japanese Army Technical Bureau shifted its attention to self-propelled

multiple rocket launcher A multiple rocket launcher (MRL) or multiple launch rocket system (MLRS) is a type of rocket artillery system that contains multiple launchers which are fixed to a single platform, and shoots its rocket ordnance in a fashion similar to a volle ...

s instead. An additional three units were produced before the

surrender of Japan The surrender of the Empire of Japan in World War II was announced by Emperor Hirohito on 15 August and formally signed on 2 September 1945, bringing the war's hostilities to a close. By the end of July 1945, the Imperial Japanese Navy ...

, but none were used in combat.

Notes

References

* * *

External links

Taki's Imperial Japanese Army Page - Akira Takizawa
{{WWIIJapaneseAFVs World War II self-propelled artillery 300 mm artillery Mitsubishi Military vehicles introduced from 1940 to 1944