Coba jelasin August: Soviet counterattack dari Pertempuran Khalkhin Gol dalam bahasa melayu dong

With war apparently imminent in Europe, Zhukov planned a major offensive on 20 August to clear the Japanese from the Khalkhin Gol region and end the fighting. Zhukov, using a fleet of at least 4,000 trucks (IJA officers with hindsight dispute this, saying he instead used 10,000 to 20,000 motor vehicles) transporting supplies from the nearest base in Chita (600 kilometres 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 and two more tank brigades (in all, some 498 BT-5 and BT-7 tanks), two motorized infantry divisions, and over 550 fighters and bombers. The Mongolians committed two cavalry divisions.Drea, Edward J. "Leavenworth Papers No. 2 Nomonhan: Japanese Soviet Tactical Combat, 1939 – BIG MAPS – Map 6"  – Retrieved: 13 May 2007.

In comparison, at the point of contact the Kwantung Army had only General Komatsubara's 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 accurately 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 defences prior to their main assault on the 20th, the Soviets launched three aggressive probing assaults, one on the 3rd and the others on the 7/8th. 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. Moreover, the Japanese counter-attacked 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 the 20th, 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's headquarters and supply elements. In addition, the growing casualty count meant that the already 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, who were free to hand-pick select units from across their entire 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 defended the east bank of the Khalkhyn Gol. Three infantry divisions and a tank brigade crossed the river, supported by massed artillery and 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 at Nomonhan village on 25 August, the Japanese 23rd Infantry Division was trapped. 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 also 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.

Komatsubara refused to accept the outcome and prepared a counteroffensive. This was canceled when a cease-fire was signed in Moscow.  While Zhukov defeated the Japanese forces on Soviet territory, Joseph Stalin had made a deal with Nazi Germany. After the Soviet success at Nomonhan, Stalin decided to proceed with the Molotov–Ribbentrop Pact, which was announced on 24 August.

With no further threat of a second front from Japan, Stalin was free to concentrate on war in Europe and the Soviet Union and Japan agreed to a cease-fire on 15 September, which took effect the following day 1:10 pm.Goldman p. 163, 164 Free from a threat in the Far East, Stalin proceeded with the Soviet invasion of Poland on 17 September.