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Posted on Mar 4, 2014 in Armchair Reading

CDG 61 – Japanese Defense of Nomonhan, 1939

CDG 61 – Japanese Defense of Nomonhan, 1939

By Armchair General

The March 2014 issue of Armchair General® presented the Combat Decision Game “Japanese Defense of Nomonhan, 1939.” This CDG placed readers in the role of Major Tomiji Kajikawa, commander of 2d Battalion, 28th Infantry Regiment, 7th Infantry Division in Japan’s Kwantung Army.

In 1931, expansionist Imperial Japan had seized and occupied Manchuria in northeast China, establishing a Japanese puppet state it renamed Manchukuo. Beginning in 1938, the aggressive actions of Japan’s occupying force, the Kwantung Army – which often operated independent of Tokyo’s control – provoked numerous clashes with Soviet and Mongolian forces over disputed boundary lines in sections of the long border Manchukuo shared with the USSR and its communist client state Mongolia.

By 1939, this series of escalating border clashes constituted an undeclared war between Japan and the Soviet Union. In mid-May of that year, the fighting became focused in western Manchukuo along the Khalkhin Gol River (which the Japanese claimed was the dividing line), 10 miles west of the village of Nomonhan (which the Soviets and Mongolians asserted was the actual border). By early July, substantial Japanese, Soviet and Mongolian infantry and mechanized forces had moved into this disputed territory and were fighting for control of it.

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Kajikawa’s mission on July 7, 1939, was to defend against a two-pronged attack a strong Soviet infantry and tank force had launched east across the Khalkhin Gol River. The Soviets aimed to destroy the outnumbered Japanese battalion and then move on to capture Nomonhan, thereby re-establishing the Soviet-claimed border line.


Although the Soviet force outnumbered Kajikawa’s battalion and included tanks – while the Japanese had none – its tactical disposition proved seriously flawed. The Soviet commander unwisely placed his company to the northwest beyond the supporting range of his main infantry-tank force to the south. This disposition exposed one-third of his infantry force to destruction, thereby putting at risk the success of his overall attack.

Kajikawa capitalized on his Soviet counterpart’s blunder by sending two Japanese infantry companies and the anti-tank guns to block the main Soviet infantry-tank force approaching from the south while directing Captain Kinichi’s infantry company to ambush the enemy company to the northwest advancing across the Khalkhin Gol River (COURSE OF ACTION THREE: COMPANY AMBUSH). Kajikawa then positioned his artillery platoon and heavy machine-gun company in the center to support both Japanese forces.

After the northwest Soviet company and its two supporting 76 mm guns crossed the river and moved several kilometers east, Kinichi’s infantry company ambushed the enemy force and, with the help of artillery and heavy machine-gun fire, killed more than 100 of its 150 Soviet soldiers. The routed enemy survivors retreated westward across the Khalkhin Gol, leaving behind the bodies of their slain comrades as well as two heavy machine guns and both 76 mm artillery guns.

With the destruction of the northwest company, the enemy’s two-pronged attack collapsed, compelling the Soviet commander to halt his main force’s assault in the south and to withdraw. This allowed Kajikawa to move his battalion southwest and seize a key bridge over the Khalkhin Gol River to use it to support future offensive operations the Kwantung Army had planned against Soviet and Mongolian forces.

Yet despite Kajikawa’s success on July 7, the Soviets won a decisive victory in the series of battles that unfolded from May to mid-September 1939, which were collectively known to the Japanese as the Nomonhan Incident and to the Soviets as the Battle of Khalkhin Gol. The four-month-long struggle eventually involved 75,000 Japanese soldiers against 60,000 Soviet and Mongolian troops and featured significant numbers of tanks, artillery and aircraft supporting the two sides’ infantrymen. The key to the Soviet victory was the strategy, operational skill and leadership of future Marshal of the Soviet Union Georgi Zhukov, whose August 20-31 offensive encircled and decisively defeated the main Japanese force.

The battle had far-reaching consequences for both the USSR and Japan. The two sides signed a neutrality pact that eliminated the threat of a two-front war for the Soviets when Germany invaded Russia in 1941 and allowed the USSR to concentrate its forces solely against the German invasion. The Japanese military’s failure in the Nomonhan Incident against the Soviets in the “North” was an important factor in Japan’s decision to instead strike “South” and launch World War II in the Pacific against the United States and Britain in December 1941.


ACG judges based their selections for winning Reader Solutions and those receiving honorable mention on submissions that chose COURSE OF ACTION THREE: COMPANY AMBUSH or those whose explanations demonstrated a solid understanding of the key principles of a defense against a multiple-axis attack. (See “After Action Report.”) This plan allotted a sufficient force to block the Soviet main attack in the south while taking maximum advantage of the Soviet commander’s tactical error of isolating his northwest company beyond the supporting range of his main force. Fighting from ambush positions, Kinichi’s infantrymen were able to bring concentrated rifle, artillery and heavy machine-gun fire against the Soviets and destroy them while avoiding unnecessary exposure to enemy fire. By centrally positioning the Japanese artillery and heavy machine guns, Kajikawa made the best use of his available fire support.

Although COURSE OF ACTION ONE: HOLD AND STRIKE offered Kajikawa’s battalion the strongest defense against the main enemy tank-infantry force approaching from the south, it relied on the Japanese artillery and heavy machine guns to act alone against the Soviet company attacking from the northwest. This plan likely would have led to failure, as the artillery and machine guns should have been deployed in conjunction with a substantial infantry force to prevent the Soviets from maneuvering to evade the weapons’ rounds.

COURSE OF ACTION TWO: COMPANY COUNTERATTACK probably was the worst plan for this tactical situation, as it mirrored the Soviet commander’s mistake by giving the enemy an opportunity to cut off and destroy the Japanese counterattacking company, which accounted for one-third of Kajikawa’s battalion. By operating on the far side of the river beyond the range of the battalion’s infantry and fire support units while attacking a superior enemy force of infantry and artillery – essentially a “banzai charge” over open terrain – the counterattacking company would have been in danger of being annihilated by the Soviets, thereby putting the battalion’s defense at risk of collapsing.


Key Points for a Defense Against a Multiple-Axis Attack

  • KNOW how the enemy fights tactically and plan accordingly.
  • IDENTIFY the main enemy attack and allocate sufficient forces to oppose it.
  • TARGET the weakest enemy force for destruction.
  • EXPLOIT enemy weaknesses and tactical errors.
  • EMPLOY all available firepower to provide continuous fire support.
  • CAPITALIZE on terrain/weather to delay enemy movement and neutralize enemy fire.
  • MAINTAIN the central position to retain flexibility to react to tactical developments.
  • MANEUVER defensive forces only within supporting distance.

1 Comment

  1. First off thank you for a great, informative and fun publication.

    That being said I have a few issues with the solution to this CDG.
    First is the way that COA 2 is described in the game itself versus how it is described in the solution.
    From the game:
    “The next option,” you continue, “is to beat the enemy at his own game. The Soviet commander intends for his force crossing the river to envelop our battalion from the north and then smash it against his larger force in the south. But under this second plan, we will use two infantry companies, the anti-tank company and half of the heavy machine-gun company to defend in the south, while Captain Kinichi’s Company 6, supported by our artillery platoon and the other half of the heavy machine-gun company, launches an enveloping counterattack to hit the exposed flank of the enemy force crossing the river. Although Kinichi’s infantrymen will be outnumbered, this surprise counterattack combined with our men’s superior élan will make them an irresistible force that will sweep over the enemy.”
    The key phrase:
    “..launches an enveloping counterattack to hit the exposed flank of the enemy force crossing the river…”
    From the Solution:
    “…By operating on the far side of the river beyond the range of the battalion’s infantry and fire support units while attacking a superior enemy force of infantry and artillery – essentially a “banzai charge” over open terrain – the counterattacking company would have been in danger of being annihilated by the Soviets, thereby putting the battalion’s defense at risk of collapsing.”
    In the former there is no mention of the Japanese going over to the far side of the river to attack the Russians. If that is what the author meant by an enveloping attack, than the Japanese would have hit the rear of the Soviet forces and not their exposed flank.
    But why would an experienced commander even consider risking his numerically inferior forces becoming disorganized while they crossed the river only to try and attack the other force while they are in the act of crossing? The commander wouldn’t, and in this case the intent was for Company 6 to launch a flanking attack on the Soviets from the east bank while they crossed the river (not the Japanese).
    COA 2 was also not just a “…bonsai charge” over open terrain…” The terrain east of the river provided light scrub and gently rising hills according to the description in the scenario, so it would not have made sense to place the machine guns and artillery in the open along the river valley.
    Another issue is the attack itself. While using an ambush to attack a numerically superior force is a tried and true method, so is attacking a force while they are in the act of crossing an obstacle. The difference is that for ambushes to work you have to have more than a reasonable assurance that the enemy will walk into your ambush or multiple ambush forces set in place. This CDG and the description of the scenario included none of that.
    Furthermore, had the Russians gone further north, or drifted to the southeast the ambush would have failed. The Japanese won this encounter due more to luck and a tactical error made by the Soviet commander than to skill.
    In future Combat Decision Games it would be useful if tactical graphics were included with each course of action so that the graphics and the words together made for a complete and unambiguous picture of the action intended.
    Armchair General is a great publication and in its 10th year we can only expect more and better things. To that end do not hold back on one of the departments that has come to define the magazine.


  1. CDG Command Center | Armchair General | Armchair General Magazine - We Put YOU in Command! - […] March 2014 Japanese Defense of Nomonhan, 1939 PDF Pullout Historical Outcome […]
  2. Armchair General July 2014 Issue – The Longest Day 70th Anniversary | Armchair General | Armchair General Magazine - We Put YOU in Command! - […] YOU COMMAND SOLUTION Historical outcome and winning Reader Solutions to Combat Decision Game #61, Japanese Defense of Nomonhan, 1939. …

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