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Type 99 81mm

Imperial Japan (1939)

Detailing the development and operational history of the Type 99 81mm Infantry Field Mortar.

 Entry last updated on 1/23/2017; Authored by Staff Writer; Content ©

  Type 99 81mm  
Picture of Type 99 81mm Infantry Field Mortar

The Type 99 of 1939 was an infantry-level field mortar for Japanese ground forces in World War 2.

As with other participants of World War 2 (1939-1945), the Imperial Japanese Army (IJA) adopted several different types of infantry-level field mortars. In 1939 came about a new design of 81mm caliber designated the "Type 99" (after the Japanese calendar year of "2599"). The Type 99 was a short-tube weapon and classified as a compact "trench mortar" during a time when it was believed that wars would still be fought through "Trench Warfare" as it was in World War 1 (1914-1918).

The Type 99, as a complete weapon system, showcased a weight of 53lb and a length of over two feet. Its launch tube measured just over a foot long. A bipod assembly, hinged to affect elevation, was affixed under the muzzle and a basic rectangular plate was fitted at the tail end of the unit. The baseplate measured over two feet wide.

The Type 99 fired 81mm shells of 7lb weight out to an effective range of 710 yards (650 meters). Absolute range was near 2,200 yards (2,000 meters). The loading system was entirely manual as most weapons of this class were. The integral mounting hardware allowed for an elevation span of +45 to +85 degrees and the projectiles exited the muzzle at 270 feet per second.

Available ammunition types included the standard explosive type, a smoke round (parachute), signal round (green smoke), mine dispenser round and a chemical round. The projectile was a self-contained munition featuring the primer cartridge, propellant charge, percussion fuze and spring-loaded fins for stabilization during the flight path. Projectiles detonated upon impact or - with some operator interference - through delayed action.

Type 99 mortars were in use until the end of the war in 1945.
Any available statistics for the Type 99 81mm Infantry Field Mortar are showcased in the areas immediately below. Categories include basic specifications covering initial year of service, country-of-origin and manufacture(s) involved in bringing the weapon to market. Other qualities showcased are related to physical values such as the internal action, available calibers / chamberings, weight and lengths. Global operators are also presented in A-to-Z format as are any model variants available to the series.
Type 99 81mm Specifications
National Flag Graphic
Imperial Japan
Year: 1939
Type: Infantry Field Mortar
Manufacturer(s): State Factories - Japanese Empire
Supported Mission Types
Frontline Infantry
Special Forces
Close Quarters Battle
Designated Marksman/Sharpshooter
Area Effect/Suppression
Indirect Fire
Airspace Denial
Attachment Weapon
Internal Design, Weight and Dimensions
Firing Action: manual loading; primer actuated
Available Caliber(s): 81mm
Ammunition Count / Feed: Single-Shot
Weight (Empty): 55.12 lb (25.00 kg)
Overall Length: 717 mm (28.23 in)
Barrel Length: 552 mm (21.73 in)
Sighting Assist: Included Optics

Operating Performance
Muzzle Velocity: 270 ft/sec (82 m/sec)
Rate-of-Fire (RoF): 6 rounds-per-minute (rpm)
Typical Range: 2,135 feet (651 m; 712 yd)

Operators List
Imperial Japan

Model Variants
• Type 99 - Base Series Designation