Detail of mosaic commemorating the Mongolian-Soviet victory over Japan in 1939, Ulaanbaatar
Courtesy Steve Mann

In the late 1920s and the early 1930s, the army frequently was called on to put down widespread popular revolts led by nobles and monks (see Purges of the Opposition, 1928-32 , ch. 1). The revolts erupted from a basic feeling of nationalism (particularly in western Mongolia), from opposition to the pro- Soviet line, and from the government's extreme measures in forcing collectivization of stock raising and harsh actions against the monks. The revolts culminated in an uprising by 13 detachments of more than 3,000 troops in April 1932 it was put down by the Mongolian army, assisted by a large Soviet Red Army force. By the mid-1930s, the communist government had suppressed the insurgency. It then decided that a more reliable army was necessary, both for internal security and for actions as a forward screen for Soviet troop deployment in the event of a Japanese invasion.

As the army recovered from the revolt, it began rebuilding. The number of young Mongolians on active duty increased annually. During this period, the army acted as an important unifier of the population, in effect supplanting the liquidated monasteries in this role. In striving for national reinvigoration, the army's military role was less important than its social and political roles. A Soviet observer wrote that the army taught the soldier to read and write the national language and converted him into a politically aware soldier-citizen. Soviet arms and military equipment were provided to the expanding army, and Soviet officers acted not only as instructors, but also as unit advisers and commanders. These arrangements were formalized first in November 1934, when a Mongolian-Soviet "gentlemen's agreement" was reached in Moscow to provide for mutual assistance in the event of attack. This accord was unpublished, because Moscow still nominally recognized the Chinese government (see Economic Gradualism and National Defense, 1932-45 , ch. 1).

Monasticism directly inhibited military buildup. Therefore, it was imperative that the monasteries be dealt with. During the period of the "leftist deviation" in the early 1930s, almost half the monasteries had been closed. This policy was relaxed during the insurrectionary period between 1933 and 1936, however, and the monasteries were reopened. By 1936 the monastic population had increased by 10,000 to more than 100,000--11 percent of the total population and 35 percent of men of military age. This drain adversely affected the government's ability to meet the increasing personnel requirements both for defense and for economic production. Monastic influence also perpetuated a general lack of interest among the general population in establishing an effective national army. The government, therefore, undertook 2000 k drastic measures against the monks. Monasteries were taxed severely for each monk of military age who did not respond to the military call-up. A law was passed requiring the first son of every family to enter the army when of age the second son was to remain with the family to work only the third son was permitted to enter the monastery. Because few Mongol families had more than two sons, this measure was effective in diminishing the monastic population. Monastic power was reduced, senior monks were liquidated, and monks of middle- rank were imprisoned. Finally, ordinary monks were forced out of the monasteries, which then were destroyed, and all monastic livestock (10 to 15 percent of the national total) was confiscated. By 1939 these repressive measures had ended monasticism and had released a substantial reservoir of manpower for military service and for the civilian economy.

Japan's occupation and annexation of neighboring Manchuria in 1931 left no doubt of Tokyo's long-range objectives in Northeast Asia. A program of subversion among the Mongolians and of agitation in support of pan-Mongolism was followed by minor clashes along the Mongolian-Manchurian border in 1934 that reached major intensity in 1935. After serious clashes with the Japanese along the eastern Mongolian border in early 1935, a conference of Mongolian and Japanese representatives was convened in June at the Chinese border town of Manzhouli to settle border demarcation and other matters. After six months without reaching agreement, the effort was abandoned. On March 1, 1936, Josef Stalin publicly and unequivocally stated that "If Japan should venture to attack the Mongolian People's Republic and encroach upon its independence, we will have to help the Mongolian People's Republic...just as we helped in 1921...." Two weeks later, a Protocol Treaty of Friendship and Mutual Assistance reiterated the main provisions of the 1934 agreement. Apparently the Soviets at the time were less concerned about Chinese sensibilities than they had been earlier. The protocol was to run for ten years it provided for joint consultation and protective action in the event of threat to either party by a third power, for military assistance in the case of a third-power attack, and for the stationing of troops in each other's territory as necessary. Some Soviet troops had remained in Mongolia after the suppression of the revolts when Japan invaded northern China and occupied Inner Mongolia, this treaty provided a basis for increasing Soviet strength to a reinforced corps, the Fifty- seventh Independent Rifle Corps.

In 1937 the Japanese invaded northern China, which enabled Japanese forces to occupy the Inner Mongolian provinces of Qahar and Suiyuan along Mongolia's southern border. This widened the zone of contact between Mongolian and Japanese forces and increased Mongolian security problems. Incidents continued along the Mongolian borders with Manchuria and Inner Mongolia. In July 1938, the Japanese Guandong (Kwantung in Wade-Giles romanization) Army (the Japanese army in Manchuria, 1931-45) mounted a major, yet unsuccessful, attack against Soviet positions in an ambiguously demarcated area along the Manchurian-Siberian border near Vladivostok. Frustrated along the Siberian border, Japan turned the following year to the more vulnerable Mongolian border, where it thought that subversion against the Mongolians would pave the way.

Mongolia's easternmost portion is a salient jutting deep into Manchuria (see fig. 1). A branch railroad runs from Changchun on the Shenyang-Harbin railroad to within a few kilometers of the border on the other side of the frontier, the Halhin Gol runs parallel to the border on the Mongolian side for about 70 kilometers. This area had been the scene of serious clashes in early 1935. To facilitate military deployment into this vulnerable area, the Soviet Union built a wide-gauge railroad, completed in 1939, connecting the Chinese-Eastern railroad to the Mongolian town of Choybalsan. The frequency of border clashes increased until they occurred almost daily in this area during 1938 and early 1939. In early May 1939, Soviet foreign minister Vyacheslav M. Molotov issued another stern warning to Japan: "I give warning that the borders of the Mongolian People's Republic will be defended by the USSR as vigorously as we shall defend our own borders."

On May 11, 1939, the Japanese army occupied portions of Mongolia between the border and the Halhin Gol. A combined Mongolian-Soviet force quickly moved against the invaders. By the end of May, the joint force had seized a bridgehead on the Halhin Gol's eastern bank. To counter this move, the Japanese by early July concentrated a corps of 38,000 troops and attacked the northern flank of the Mongolian-Soviet bridgehead. The Japanese drove the allies back across the Halhin Gol, crossed it themselves, and established their own bridgehead on the western bank. On July 5, 1939, Soviet armor counterattacked and eliminated the Japanese bridgehead, after which both sides began a major force buildup.

During July 1939, the Mongolian-Soviet forces were reorganized. The Trans-Baykal Military District was set up as a front headquarters, with the First Army Group under General Georgi Zhukov as the striking force. Soviet forces were concentrated in eastern Mongolia, and the Mongolian army mobilized to its full strength of 80,000 in eight cavalry divisions the 515 aircraft of the combined force were used mostly in screening the southern borders. Zhukov's First Army Group included Mongolia's Sixth and Eighth Mongolian cavalry divisions, both of which were employed as flank protection for the army group along the 70-kilometer front on the Halhin Gol. During July and early August, the Japanese forces, setting August 20, 1939, as the target date, prepared to cross the river and to destroy the opposing forces.

The Japanese decision to attack must have been based on faulty intelligence or on extreme overconfidence, because the Japanese were weaker in infantry battalions by 30 percent, in tanks by 60 percent, and in aircraft by 25 percent. Further, Soviet intelligence was superior to the Japanese, because the Soviets had detected the Japanese buildup for the attack and had evidently correctly estimated its timing. At dawn August 20, 1939, the commander of the Mongolian-Soviet troops preempted the Japanese attack: 150 bombers struck Japanese positions, rear areas, and lines of communication. A ground attack by the southern and the northern wings of the First Army Group penetrated the Japanese flank with armor and infantry, and then they turned inward in a classic double envelopment as Mongolian cavalry protected the outer flanks.

The Japanese defended tenaciously, but by August 23 the Soviets had encircled the Japanese forces along the Halhin Gol. For five days, the Mongolian-Soviet forces beat back fierce attacks by Japanese relief forces as well as attempts by the surrounded units to break out. Japanese relief attempts slackened, and pockets of resistance were cleared out. On August 31, 1939, the Mongolian-Soviet forces advanced to the frontier. The Japanese conceded defeat and a cease-fire took effect on September 16, 1939.

Soviet casualties came to nearly 10,000, and the Mongolians lost 1,130. Japanese losses were far greater, with more than 18,000 killed and 25,000 wounded (some total estimates were as high as 80,000). More than 170 guns and 200 aircraft were lost. After the defeat, Japan turned its military thrust southward. On June 9, 1940, an agreement fixing the Manchukuo-Mongolian border was signed in Moscow. This was followed on April 13, 1941, by the Soviet-Japanese Neutrality Pact, which included a Soviet pledge to recognize the territorial integrity of Manchukuo and a similar Japanese pledge with respect to Mongolia. Germany's invasion of the Soviet Union in June 1941 and the entry of the United States into World War II in December fully committed the Soviet Union and Japan to other flanks of their respective domains thus, their Mongolian flanks rema6f0 mained relatively quiet until the final weeks of World War II.

Mongolia stayed mobilized, however, at the 80,000-troop level to guard its frontiers and to discourage any further Japanese incursion. Mongolia also devoted extensive resources to its part of the 1936 mutual-assistance pact, providing the Soviet armed forces with winter clothing, wool, hides, leather goods, meat, and almost half a million ponies and horses for draft and remount use from 1941 to 1945. The Mongolian people raised the money for a brigade of tanks, named the Revolutionary Mongolian Tank Brigade, and for a squadron of aircraft, named Mongolian Herdsmen, presented to the Red Army. In August 1945, Mongolian and Soviet forces joined in the invasion of Manchuria and Inner Mongolia, destroyed the greatly weakened Japanese army, and achieved Soviet political and military goals in northeastern Asia.

Data as of June 1989