May: Skirmishes The battles began on 11 May 1939. A Mongolian cavalry unit of 70 to 90 men had entered the disputed area in search of grazing for their horses. On that day, Manchu cavalry attacked the Mongolians and drove them back across the river Khalkhin Gol. On 13 May, the Mongolian force returned in greater numbers and the Manchukoans failed to dislodge them. On 14 May, Lt. Col.
Yaozo Azuma led the reconnaissance regiment of the 23rd Infantry Division, supported by the 64th Infantry Regiment of the same division, under Colonel
Takemitsu Yamagata, into the territory, and the Mongolians withdrew. Soviet and Mongolian troops returned to the disputed region however, and Azuma's force again moved to evict them, but the Soviet-Mongolian forces surrounded Azuma's force on 28 May and destroyed it. The Azuma force suffered eight officers and 97 men killed, and one officer and 33 men wounded, for 63% total casualties.
June: Escalation Both sides increased their forces in the area. On 5 June, Zhukov, the new
corps commander, arrived, and brought more motorized and armored forces (I Army Group) to the combat zone. Accompanying Zhukov was Comcor
Yakov Smushkevich with his aviation unit.
Zhamyangiyn Lhagvasuren, Corps Commissar of the
Mongolian People's Revolutionary Army, was appointed Zhukov's deputy. On 27 June, the
Japanese Army Air Force's
2nd Air Brigade struck the Soviet airbase at Tamsak-Bulak in Mongolia. The Japanese won this engagement, but the strike had been ordered by the Kwantung Army without obtaining permission from
Imperial Japanese Army (IJA) headquarters in Tokyo. In an effort to prevent the incident from escalating, Tokyo promptly ordered the JAAF not to conduct any more air-strikes against Soviet airbases. armored car or an
I-153) cavalry tank surrendering to the Japanese Throughout June, there were reports of Soviet and Mongolian activity on both sides of the river near Nomonhan, and small-scale attacks upon isolated Manchukoan units. At the end of the month, the commander of the 23rd Japanese Infantry Division, Lt. Gen. Michitarō Komatsubara, received permission to "expel the invaders".
July: Japanese assault The Japanese planned a two-pronged assault. The first attack would be made by three regiments plus part of a fourth: the 71st and the 72nd Infantry Regiment (23rd Division), a battalion of the 64th Infantry Regiment and the 26th Infantry Regiment under Colonel Shinichiro Sumi (7th Infantry Division). This force would advance across the Khalkhin Gol, destroy Soviet forces on Baintsagan Hill on the west bank, then make a left turn and advance south to the Kawatama Bridge. The second prong of the attack would be the task of the IJA 1st Tank Corps (1st TC) (
Yasuoka Detachment), consisting of the
3rd and
4th Tank Regiments, plus a part of the 64th Infantry Regiment, a
battalion from the 28th Infantry Regiment, detached from the 7th Infantry, 24th Engineer Regiment, and a battalion from the 13th Field-Artillery Regiment, all under the overall command of
Lieutenant General Yasuoka Masaomi. This force would attack Soviet troops on the east bank of the Khalkhin Gol and north of the Holsten River. The two Japanese thrusts were to join on the wings. The order of battle was thus: • Lt. Gen.
Yasuoka Masaomi, IJA, Commanding Officer, 1st Tank Corps •
3rd Tank Regiment •
Type 89 I-Go medium tanks – 26 •
Type 97 Chi-Ha medium tanks – 4 •
Type 94 tankettes – 7 •
Type 97 Te-Ke tankettes – 4 •
4th Tank Regiment •
Type 95 Ha-Go light tanks – 35 •
Type 89 I-Go medium tanks – 8 •
Type 94 tankettes – 3 The northern task force succeeded in crossing the Khalkhin Gol, driving the Soviets from Baintsagan Hill, and advancing south along the west bank. However, Zhukov, perceiving the threat, launched a counterattack with 450 tanks and armored cars. The tanks consisted of primarily
BT tanks with a handful of
T-26s, while the armored cars were
BA-10s and
BA-3/6s, which were similar in armor () and armament (main: gun 20K mod, secondary: two machine guns) to the Soviet light tanks. The Soviet armored force, despite being unsupported by infantry, attacked the Japanese on three sides and nearly encircled them. The Japanese force, further handicapped by having only one pontoon bridge across the river for supplies, was forced to withdraw, recrossing the river on 5 July. Meanwhile, the 1st Tank Corps of the Yasuoka Detachment (the southern task force) attacked on the night of 2 July, moving in the darkness to avoid the Soviet artillery on the high ground of the river's west bank. A pitched battle ensued in which the Yasuoka Detachment lost over half its armor, but still could not break through the Soviet forces on the east bank and reach the Kawatama Bridge. After a Soviet counterattack on 9 July threw the battered, depleted Yasuoka Detachment back, it was dissolved and Yasuoka was relieved.
starter truck The two armies continued to spar with each other over the next two weeks along a front running along the east bank of the Khalkhin Gol to its junction with the Holsten River. Zhukov, whose army was away from its base of supply, assembled a fleet of 2,600 trucks to supply his troops, while the Japanese suffered severe supply problems due to a lack of similar motor transport. In early July the Japanese had only 600 trucks, rising to 1,000 by the end of the month, of which only 75% were operable. By 20 August the Japanese managed to accumulate 2,000 trucks delivering 1,500 tons of supply daily, but even this fell below the Red Army's capabilities. On 23 July, the Japanese launched another large-scale assault, sending the 64th and 72nd Infantry Regiments against Soviet forces defending the Kawatama Bridge. Over a period of two days, Japanese artillery supported the attack with a massive barrage that consumed more than half of their ammunition stores. The attack made some progress but failed to break through Soviet lines and reach the bridge. The Japanese disengaged from the attack on 25 July due to mounting casualties and depleted artillery stores. By this point they had suffered over 5,000 casualties between late May and 25 July, with Soviet losses being much higher but more easily replaced. The battle drifted into a stalemate.
August: Soviet counterattack With war apparently imminent in Europe, and to avoid fighting a two-front war, Zhukov planned a major offensive on 20 August 1939 to clear the Japanese from the Khalkhin Gol region and to end the fighting. Zhukov, using a fleet of at least 4,000 trucks, and transporting supplies from the nearest base in Chita away, assembled a powerful armored force of three tank brigades (the 4th, 6th, and 11th) and two mechanized brigades (the 7th and 8th, which were armored car units with attached infantry support). This force was allocated to the Soviet left and right wings. The entire Soviet force consisted of three rifle divisions, two tank divisions plus two more tank brigades (in all, around 498
BT-5 and
BT-7 tanks), two motorized infantry divisions, and over 550 fighters and bombers. The Mongolians committed two cavalry divisions. In comparison, at the point of contact, the Kwantung Army had only the 23rd Infantry Division, which, with various attached forces was equivalent to two light infantry divisions. Its headquarters had been at Hailar, over from the fighting. Japanese intelligence, despite demonstrating an ability to track the build-up of Zhukov's force, failed to precipitate an appropriate response from below. Thus, when the Soviets finally did launch their offensive, Komatsubara was caught off-guard. To test the Japanese defenses prior to their main assault on 20 August, the Soviets launched three aggressive probing assaults, one on 3 August and the others on 7-8 August. All three were disastrously thrown back, with around 1,000 combined dead and several tanks knocked out on the Soviet side compared to just 85 Japanese casualties. The Japanese counterattacked and routed elements of the Mongolian 8th Cavalry Division, seizing a hilly sector of the battlefront. Despite the fact that no more major fighting would take place until 20 August, Japanese casualties continued to mount at a rate of 40 wounded per day. Kwantung Army staff officers were becoming increasingly worried over the disorganized state of the 6th Army headquarters and supply elements. The growing casualty count meant that the green 23rd Division would have to take, train and assimilate new replacements "on the job". By contrast, Tokyo's oft-stated desire that it would not escalate the fighting at Khalkhin Gol proved immensely relieving to the Soviets, freed to hand-pick select units from across the military to be concentrated for a local offensive without fear of Japanese retaliation elsewhere. Zhukov decided it was time to break the stalemate. At
05:45 on 20 August 1939, Soviet artillery and 557 aircraft attacked Japanese positions, the first fighter-bomber offensive in
Soviet Air Force history. Approximately 50,000 Soviet and Mongolian soldiers of the
57th Special Corps attacked the east bank of the Khalkhin Gol. Three infantry divisions and a tank brigade crossed the river, supported by massed artillery and by the Soviet Air Force. Once the Japanese were pinned down by the attack of Soviet center units, Soviet armored units swept around the flanks and attacked the Japanese in the rear, achieving a classic
double envelopment. When the Soviet wings linked up by Nomonhan on 25 August, they trapped the Japanese 23rd Infantry Division. On 26 August, a Japanese counterattack to relieve the 23rd Division failed. On 27 August, the 23rd Division attempted to break out of the encirclement but failed. When the surrounded forces refused to surrender, they were again hit with artillery and air attacks. By 31 August, Japanese forces on the Mongolian side of the border were destroyed, leaving remnants of the 23rd Division on the Manchurian side. The Soviets had achieved their objective. The Soviet Union and Japan agreed to a cease-fire on 15 September; it took effect the following day at 1:10 pm. ==Casualties==