Type 4 Ha-To

The Type 4 Ha-To (試製四式重迫撃砲 ハト, Shisei yon-shiki jū-hakugekihō hato) was a self-propelled gun developed by the Imperial Japanese Army for use in World War II.

Key Information

Type 4 Ha-To
Type 4 Ha-To self-propelled mortar
Type	Self-propelled artillery/self-propelled mortar
Place of origin	Empire of Japan
Production history
No. built	4
Specifications
Mass	14.3 tons
Length	6.8 meters
Width	2.4 meters
Height	2.75 meters
Crew	7
Armor	12–25 mm
Main armament	Type 3 300 mm mortar
Secondary armament	none
Engine	water-cooled 6-cyl Mitsubishi gasoline 115 hp (86 kW)
Power/weight	-
Suspension	bellcrank
Maximum speed	40 km/h
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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 medium tank and on the Type 4 Chi-So armored medium tracked carrier.^[1][2][3] The armor was "thinner" than the Chi-To and the engine compartment was moved to the front.^[2] The mortar had a range of 3,000 m (1.9 mi) and launched a 170 kg (374 lb) projectile. The gun itself weighed close to 1.5 tons, and to keep the center of gravity from shifting and tipping the vehicle over, it could not be elevated more than 50 degrees. For transportation the barrel was laid horizontal and when set to fire, the rear and baseplate were lowered down to the ground.^[4]

The first prototype was completed in late 1944 and taken to the Imperial Japanese Army Academy 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 launchers instead, which were easier to produce.^[1][5]

An additional three units were produced before the surrender of Japan, but none were used in combat.^[6]

• Ness, Leland (2014). Rikugun: Guide to Japanese Ground Forces, 1937-1945. Volume 2, Weapons of the Imperial Japanese Army & Navy Ground Force. Helion and Company. ISBN 978-1909982758.
• Tomczyk, Andrzej (2003). Japanese Armor Vol. 3. AJ Press. ISBN 978-8372371287.
• Tomczyk, Andrzej (2007). Japanese Armor Vol. 5. AJ Press. ISBN 978-8372371799.
• Trewhitt, Philip (1999). Armoured Fighting Vehicles. Dempsey-Parr. ISBN 978-1840843286.

• Taki's Imperial Japanese Army Page - Akira Takizawa