Japanese World War Two Mortars

[Robert Hurst]

Hi

Grenade Dischargers

50 mm Type 10

First produced in 1921 the type 10 grenade discharger was the first of two grenade launchers used by the infantry to propel small grenades to a range of up to 160 m. In use the spade base was placed on the ground and the barrel hand-held at an angle of 45 degrees. Range was altered by opening a gas port - the wider the port the more the gas could escape and thus the range was reduced. Firing was accomplished by pulling on a lanyard which set off the trigger mechansism to detonate the propelling charge in the base of the grenade. The usual HE grenade was the Type 91, but there were smoke, flare and signal grenades.

By 1941 the Type 10 had beem largely replaced by the later Type 89, but the Type 10 was kept on for firing pyrotechnics. The Japanese designaiton was Junen Shiki Tekidanto, but to the Allies it was often referred to as the 'Knee mortar', an incorrect dexcription that led to many broken legs.

Data:

Calibre: 50 mm (1.97 in)
Barrel length: 241 mm (9.5 in)
Overall length: 508 mm (20 in)
Weight: 2.38 kg (5.25 lb)
Maximum range: 160 m (175 yds)
Minimum range: 60 m (65 yds)
Bomb weight: 0.53 kg (1.17 lb)

50 mm Type 89

The Type 89 grenade discharger first appeared in 1929 and differed from the earlier Type 10 in having a rifled barrel. Another difference was that the gas port was eliminated in favour of a firng pin that could be moved up and down the barrel to alter the range, and a larger curved base pate was fitted.

The Type 91 grenade could be fired from this discharger but the more usual grenade was the Type 89 shell. Other possible rounds were smoke, incendiary, flare and signal grenades. The Type 89 could be fired to a range of 650 m (710 yds) and was thus quite an addition to an infantry shqaad's firepower. Full Japanese designation was Hachikyu Shiki Jutekidanto. For use by paratroops a special version was developed that used adeatchable base plate.

Data:

Calibre: 50 mm (1.97 in)
Barrel length: 254 mm (10 in)
Overall length: 610 mm (24 in)
Weight: 4.65 kg (10.25 lb)
Maximum range (Type 91): 190 m (208 yds)
Maximum range (Type 89): 650 m (710 yds)
Minimum range (Type 89): 120 m (131 yds)
Bomb weight (Type 89): 0.79 kg (1.75 lb)

The above text and photos were taken from "WWII Fact Files: Mortars", by Terry Gander and Peter Chamberlain.

Regards

Bob

[Robert Hurst]

Hi

50 mm Type 98

The 50 mm Type 98 entered service in 1938 and was a specialised demolition mortar. It consisted of a steel barrel preset to a fixed angle of 40 degrees on a base plate, and it fired a stick grenade to a range of 416 m (455 yds).

The stick grenade had a large square head that contained about 7 lb of pricri acid blocks which could produce a considerable blast effect and were very useful in attacking and neutralising strong points durng an attack. In use, the barrel was loaded with a black powder charge in a silk bag. The 50 mm diameter stick grenade was then loaded into the barrel to a preset depth - the more the depth, the greater the range. The charge was fired by pulling on a lanyard from a safe distance. As well as firing the stick grenade, the Type 98 could also fire a bangalore torpedo to clear minefields.

Data

Calibre: 50 mm (1.97 in)
Barrel length: 650 mm (25.6 in)
Weight: 22.5 kg (49.6 lb)
Elevation: 40 degrees - fixed
Traverse: 7 degrees
Maximum range (HE): 416 m (455 yds)
Bomb weight: 6.4 kg (14.1 lb)

70 mm Type 11

The Japanese referred to their Type 11 mortar as a high angle infantry gun as it had a rifled barrel. However, it still used muzzle-loading and thus qualifies as a mortar.

It was rather a heavy weapon best suited for use in static situations, and it fired grenades that were enlarged versions of those used in the Type 89 grenade discharger. Firing was by percussion hammer.

This mortar, the full Japanese designation for which was Juichinen Shiki Kyokusha Hoheio, entered service in 1922 but by 1942 it had been withdrawn form general use.

Data

Calibre: 70 mm (2.76 in)
Weight emplaced: 60.7 kg (133.75 lb)
Elevation: 37 to 77 degrees
Traverse: 23 degrees
Maximum range (approx): 1,555 m (1,700 yds)
Bomb weight: 2.1 kg (4.67 lb)

81 mm Type 3

The Type 3 81 mm mortar was a direct copy of the ubiquitour Stkes-Brandt design and was first issued in 1928. It closely resembled all the other 81 mm Brandt designs and there was little of note about this weapon, except that production was still continuing at Yokosuka Navy Arsenal in 1943.

Data

Calibre: 81.4 mm (3.2 in)
Barrel length: 1,257 mm (49.5 in)
Weight: 74.8 kg (167 lb)
Maximum elevation: + 85 degrees
Bomb weight (HE): 6.5 kg (14.3 lb)
(HE): 3.27 kg (7.2 lb)

The above text and photos except 50 mm Type 98 b were taken from WW11 Fact Files: Mortars. Photo Type 98 b was taken from TAKI's Imperial Japanese Army site.

Regards

Bob

[Marcus]

Interesting info, thanks.

/Marcus

[Robert Hurst]

Hi

81 mm Type 97

The Type 97, or to give the Japanese designation, the Shiki Kyokusha Hoheiho, was first issued in 1937 and was the revised 'Japanese' version of the Type 3 which was a copy of a French design. It was very similar to the Type 3 but was generally lighter, even though the same base plate as that fitted to the Type 3 was used.

The main change was that the bore tolerances were very closely machined which led to a resultant retention of gases on firing. Thus, a shorter barrel could produce a better range than one with the usual amount of windage. The Type 97 became one of the two 'standard' Japanese infantry mortars and was encountered on all fronts.

Data

Calibre: 81 mm (3.19 in)
Barrel length: 1,257 mm (49.5 in)
Bore length: 1,162 mm (45.
Weight: 65.9 kg (145.125 lb)
Maximum elevation: + 85 degrees
Maximum range (14.3 lb): 1,200 m (1,312 yds)
Maximum range (7.2 lb): 3,001 m (3,280 yds)
Bomb weight (HE): 6.5 kg (14.3 lb)
Bomb weight (HE): 3.27 kg (7.2 lb)

81 mm Type 99

First issued in 1939, the Type 99 carried the close machining of the barrel first used on the Type 97 one stage further to produce a shorter and lighter weapon which had a performance identical to that of the longer Type 97.

It also featured an alternative trigger mechanism which could be used instead of the normal fixed firing pin system. The Type 99, or Kyukyu Shiki Shohakugekiho, became the second of the 'standard' infantry mortars and was widely used. It fired the same ammunition as the Type 97.

Data

Calibre: 81 mm (3.19 in)
Barrel length: 641 mm (25.25 in)
Weight 23.7 kg (52.25 lb)
Maximum elevation: + 70 degrees
Maximum range (14.3 lb): 1,200 m (1,312 yds)
Maximum range (7.2 lb): 3,001 m (3,280 yds)
Bomb weight: 6.5 kg (14.3 lb)
Bomb weight: 3.27 kg (7.2 lb)

The above text and photos were taken from "WWII Fact Files: Mortars", by Peter Chamberlain and Terry Gander.

Regards

Bob

[Robert Hurst]

Hi

90 mm Type 94

Known to the Japanese as the Kyuyon Shiki Keihakugehiko, the 90 mm Type 94 mortar entered service in 1934. It featured a heavy recoil mechanism and a heavily reinforced breech, and this added to the weight of the piece to such an extent that mobility was impaired.

The Type 94 thus became more of a static defence weapon or was often used as an emplaced barrage mortar, for which purpose it was furnished with a more complex dial site than was usually encountered on mortars. The Type 94 was gradually replaced by the lighter 90 mm Type 97 mortar.

Data

Calibre: 90 mm (3.54 in)
Barrel length: 1,270 mm (50 in)
Bore length: 1,219 mm (48 in)
Weight: 155 kg (341.5 lb)
Maximum elevation: + 70 degrees
Traverse: 10 degrees
Maximum range: 3,797 m (4,150 yds)
Minimum range: 558 m (610 yds)
Bomb weight: 5.22 kg (11.5 lb)

90 mm Type 97

The 90 mm Type 97 was developed to replace the heavy Type 94, and it entered service in 1937. It dispensed with the recoil mechanism of the Type 94 but the bore length remained the same so the same range could be achieved as on the heavier weapon. The same base plate and bipod as that on the Type 94 were retained and the same ammunition fired.

Data

Calibre: 90 mm (3.54 in)
Barrel length: 1,330 mm (52.375 in)
Bore length: 1,219 mm (48 in)
Weight: 105.8 kg (233 lb)
Maximum elevation: + 70 degrees
Maximum range: 3,797 m (4,150 yds)
Minimum range: 558 m (610 yds)
Bomb weight: 5.22 kg ( 11.5 lb)

The above text and photos were taken from "WWII Fact Files: Mortars", by Peter Chamberlain and Terry Gander.

Regards

Bob

[Robert Hurst]

Hi

120 mm Type 2

This effective and efficient mortar only entered production late in WWII and therefore saw only limited use.

Data

Calibre: 120 mm
Barrel length: 1,535 m
Weight: 260 kg
Elevation: + 40 to + 80 degrees
Range: 4,200 m
Bomb weight: 12.76 kg

150 mm Type 97

The largest and heaviest of the conventional Japanese mortars was the 150 mm Type 97. First issued in 1937 it was intended as a heavy bombarment weapon but as the war continued it was used as a coastal defence weapon, and some were mounted on 360 degree carriages on coastal craft. The general design was conventional and unremarkable except for its size.

Data

Calibre: 150 mm (5.9 in)
Barrel length: 1,914.4 mm (75.37 in)
Bore length: 1,676 mm (66 in)
Weight complete: 349.6 kg (770 lb)
Maximum elevation: + 80 degrees
Maximum range: 2,001 m (2,187 yds)
Bomb weight (HE): 25.88 kg (57 lb)

The data for the 120 mm Type 2 was taken from Taki's Imperial Japanese Army Page.

The data for the 150 mm Type 97 was taken from "WWII Fact Files: Mortars", by Peter Chamberlain and Terry Gander.

Regards

Bob

[haibin]

Would appreciate it very much if you can give me some clue about the type of mortar in the photo. It was taken in 1943, showing trophies from a battle in which a platoon of Japanese soliders were destroyed. Haibin