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Battlefront WWII
Japanese Artillery

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Introduction to Japanese Artillery Okinawa and Iwo Jima Japanese Artillery in Battlefront Knee Mortars Sources

WWII Japanese Artillery

First some quotes:
"Japanese use of artillery is subject to much criticism. The fundamental fault is that there is generally not enough of it. The weakness in artillery may be the result of lack of appreciation of the need for adequate fire support, or of a feeling that past experience has not demonstrated the need for stronger artillery. The period of daylight fire for adjustment prior to the fire for effect reduces tactical surprise and diminishes the moral [sic] effect of the preparation. This unwillingness to fire the preparation unobserved at night would suggest low gunnery efficiency. Also the absence of general support artillery reduces the flexibility of the artillery fires and limits the ability of the division commander to intervene promptly in the action by use of his artillery. From the picture drawn in the tactical problems, one can feel reasonably sure that the Japanese infantry will jump off, even though their extensive preparations have neither destroyed hostile wire nor neutralized the enemy artillery and machine guns. The detailed workings of the direct support fires are not described in the problems studied; hence, no estimate of their effectiveness can be made other than that implied be the absence of detailed plans for infantry-artillery liaison."

"The weakness of the division artillery makes extremely difficult the support of an operation on a wide front such as a river crossing. It becomes difficult to allot any artillery to a distant fight, without which there cannot be much deception."

"The Japanese dislike for using their light artillery at long ranges tends to keep delaying positions relatively close together (3000-4000 yards). Japanese artillery has little experience in fire with air observation."

-Handbook on Japanese Military Forces, TM-E30-480, US War Dept, Oct 1944

"The Japanese Army has neglected to keep pace with other major armies in the development of modern artillery techniques."
- from War Dept. Intell.Bulletin vol.III, No. 10 (June 1945)

How to handle Japanese artillery for a Battlefront WWII game? The above quotes give some indication - Japanese artillery is "not like the others". Because of organizational defects, it was rare and difficult for Japanese forces to mass the fire of entire artillery units, the way other WWII armies could. In the Japanese system, each artillery battery had to register its own weapons on any potential target, and once battle was joined, fire control was decentralized to each battery - there were no fire direction centers.

This decentralization of technique also applied to organization. It was quite common for the Japanese to detach a battery, a section, or sometimes even individual weapons, and use them as roving units, widely separated from the remainder of the artillery unit. Also, guns of different calibers were mixed within units, again sometimes down to section level. Different sections of a given battery were often emplaced 300-1000 yards apart from each other, and often sited in great depth within their positions (the guns were widely staggered). All of these factors greatly hindered rapid registration, massing of fires, and shifting of fires. Japanese artillery fire, for most of the Pacific War, was conducted on a section-by-section, or battery-by-battery basis (however this did facilitate the "hiding" of artillery in pillboxes and caves, where they could be very difficult to destroy).

On the other hand, Japanese artillery fire was often very accurate. It was common (especially during static or defensive situations) for a Japanese artillery battery to employ bilateral observation - an Observation Post would be established on the gun-to-target line, and another OP set up on both flanks. This permitted the center OP to concentrate on deflection adjustments while the flank OPs adjusted for range. The method was slow, but accurate.

Generally, the Japanese only fired a few guns at a time in any one sector (the exceptions came later in the war at large defensive battles such as Iwo Jima or Okinawa - see below). Even in sectors occupied by an artillery battalion or regiment, fire was often delivered by only a section or battery at a time. Generally, volleys were not fired; each section salvoed at a given rate. Sometimes each section's tubes would fire just one round each, then cease fire for a few minutes while the other sections would each fire their rounds in turn, thus keeping up a slow, steady harassing fire. It was also not unusual for a battery to fire at two or more targets simultaneously, different sections or individual guns having been assigned different fire missions. Generally, by other WWII armies' standards, few rounds were fired at any one target, but those that were, were very accurate.

In a Japanese artillery regiment or battalion, fire control duties were handled by battery commanders. The unit commander would prepare before-battle fire support plans and battery positions, but once combat was joined, artillery support generally broke down to the point where one battery supported one infantry battalion, and was not usually available to join a companion battery in rapidly adjusting to provide mass fire upon a single target. Instead, each battery or section would have its own observer whose concern would be targets appearing in his own sector. Because of this decentralization, each battery of a battalion would have to register on a new target separately, before beginning fire for effect.

Liaison between infantry and artillery units was also poor. Japanese doctrine placed heavy emphasis on the role of individual infantrymen, and the value of artillery fire tended to be held in less esteem, and infantry commanders often tried to force their idea of proper artillery support upon their supporting artillery unit, rather than let the artillery work in its own fashion.

For most of the war (most) Japanese artillery units had to work with a limited amount of ammunition, hence the slow ROF and careful ranging. Their artillery seemed almost lazy in comparison to other doctrines. An occasional round here and there-but then a sudden sharply defined volley of fire on target.

Okinawa and Iwo Jima

"During the height of the Okinawa campaign, soldiers and marines of the U.S. Tenth Army experienced Jap artillery fire on a scale never before faced by our troops in the Pacific."
- from War Dept. Intell.Bulletin Vol. III, No. 12 (Aug. 1945)

The tactics and procedures outlined in the introduction hold true as a description of Japanese artillery practice for the great majority of the Pacific war. Even as late as the fighting in The Philippines during 1944-45 saw "spotty and inefficient" use of Japanese artillery. However, increasing exposure to the devastating firepower brought to bear by the Western Allies during their drives toward Tokyo brought a new appreciation to Japanese military leaders of the power of massed modern artillery, and for the last battles, on Iwo Jima and Okinawa, they did all they could to maximize their artillery assets.

The Japanese were in no position to alter their doctrine - they hadn't the time. Consequently, to provide for massed artillery fire, they still had to operate without fire-direction centers. But they could and did provide the defenses of Iwo and Okinawa with a central artillery headquarters or "controlling authority" to plan a complete integration of all artillery units and enforce an overall fire plan. For the first time during the Pacific fighting the Japanese planned to mass the fire of several batteries, or even several whole battalions, upon single targets. They were able to do so by planning their defensive positions well in advance and then installing the available artillery in the best positions possible so as to be able to cover their defensive zones. In addition, extensive communications were set up to enable control of the various battalions/batteries. At Okinawa, the major portion of the medium and long-range artillery was grouped in the center of the defensive zone, and were situated so as to provide overlapping fields of fire.

A typical battery was located so as to provide maximum protection from aerial observation, and from air or naval bombardment. Wire communication connected the Forward Observer post with the battery. The Japanese had ample opportunity to pre-register each battery, before the battle, on check points and prospective target areas. Once the battle had begun, Battery FOs then were able to report targets to the overall artillery headquarters which in turn would order one or more batteries to fire according to their previously plotted registration. This allowed the Japanese, for the first time, to hit enemy troops with artillery concentrations immediately upon the enemy entering a particular area (though the fact that fire was not immediately received on each such occasion shows that the Japanese still had not developed a proper fire-direction center). Indeed, the Japanese fought bitterly to hold or recapture dominating terrain where artillery observation posts were maintained.

In summary, the Japanese at Iwo Jima and Okinawa, for the first time, made maximum use of their artillery assets according to their doctrine. Their observation system always provided for accurate fire; during these last battles they finally were able to combine accuracy with massed fires. The system would not have worked in other than a stable setting with plenty of preparation time, but for the 1945 battles, Japanese artillery became quite deadly.

Japanese Artillery in Battlefront:WW2

Japanese Call For Fire Table

Knee Mortars

The Japanese made extensive use of grenade dischargers, often mistakenly referred to a "Knee Mortars" (the base of the grenade discharger was curved, giving the impression that it was designed to be braced against the user's leg. However, it was really designed to be braced against a tree trunk or on the ground, and shattered the bones of those who attempted to fire it braced against their bodies). While nominally an indirect fire weapon, the grenade discharger's was really used as a company support direct fire weapon. Its special characteristics require some special rules.
  1. When engaging units within 5" Knee Mortars use Direct fire procedures and modifiers (this represents rifle fire from the crew). From 5"-15" Knee Mortars use Direct Fire procedures, but use Indirect Fire modifiers. This makes cover less effective, and also negates the "suspected target" modifier.
  2. Knee Mortars do not fire in the indirect fire phases, but fire as direct fire weapons in the Offensive, Defensive, and Overwatch fire phases. They may also conduct opportunity fire.
  3. As with other DF weapons, Knee Mortars need not emplace to fire.
  4. Even when using their indirect strengths, Knee mortars fire at individual targets.
  5. Knee Mortars may fire only at targets in their Line of Sight. As with other direct fire units, they may only fire at suspected or spotted targets. Other units may not act as observers for knee mortars.
  6. Knee Mortars fire individually. They may not engage in concentration missions.
  7. Knee Mortars may fire over intervening friendly units, but only in the 5-15" ranges AND when the intervening friendly unit is more than 2" away from the target.



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This page was last updated on 01/05/2020 at 07:07AM

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