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Type 99 81mm

Infantry Field Mortar [ 1939 ]

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

Authored By: Staff Writer | Last Edited: 01/23/2017 | Content ©www.MilitaryFactory.com | The following text is exclusive to this site.

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.©MilitaryFactory.com
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Service Year

Imperial Japan national flag graphic
Imperial Japan


Infantry Field Mortar

State Factories - Japanese Empire
(View other Arms-Related Manufacturers)
National flag of modern Japan Imperial Japan
(OPERATORS list includes past, present, and future operators when applicable)
Fire Support
Capable of suppressing enemy elements at range through direct or in-direct fire.

Overall Length
717 mm
28.23 in
Barrel Length
552 mm
21.73 in
Empty Wgt
55.12 lb
25.00 kg

Included Optics


manual loading; primer actuated

(Material presented above is for historical and entertainment value and should not be construed as usable for hardware restoration, maintenance, or general operation - always consult official manufacturer sources for such information)



Sample Visuals**

Graphical image of an infantry mortar projectile / shell
Rounds / Feed

Cartridge relative size chart
*May not represent an exhuastive list; calibers are model-specific dependent, always consult official manufacturer sources.
**Graphics not to actual size; not all cartridges may be represented visually; graphics intended for general reference only.
Max Eff.Range
2,135 ft
(651 m | 712 yd)
Muzzle Velocity
270 ft/sec
(82 m/sec)

Type 99 - Base Series Designation

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Images Gallery

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Image of the Type 99 81mm
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