The Soviet Border Service started to report an intensifying Chinese military activity in the region in the early 1960s. Tensions at first built slowly, but the
Cultural Revolution made them rise much faster. The number of troops on both sides of the Sino-Soviet border increased dramatically after 1964. Militarily, in 1961, the Soviets had 225,000 men and 200 aircraft at the border. In 1968, there were 375,000 men, 1,200 aircraft and 120 medium-range missiles. China had 1.5 million men stationed at the border and had tested its first nuclear weapon (
the 596 Test in October 1964, at
Lop Nur basin). Both sides' political rhetoric was increasingly hostile. The key moment in escalating Sino-Soviet tensions was the
Soviet invasion of Czechoslovakia on 20–21 August 1968 and the proclamation of the
Brezhnev Doctrine that the Soviets had the right to overthrow any communist government that was diverging from what was defined by the Kremlin. Mao saw the Brezhnev Doctrine as the ideological justification for a Soviet invasion of China to overthrow him and launched a massive propaganda campaign attacking the invasion of Czechoslovakia, although he had condemned the
Prague Spring as "revisionism". On 21 August 1968, the Romanian leader,
Nicolae Ceaușescu, gave a
speech in Revolution Square in
Bucharest that denounced the invasion of Czechoslovakia. It was widely seen both in Romania and abroad as virtual declaration of independence from the Soviet Union. Romania began to move away from the Soviet
sphere of influence, towards the Chinese sphere of influence. Speaking at a banquet held at the Romanian embassy in Beijing on 23 August 1968,
Zhou Enlai denounced the Soviet Union for "fascist politics, great power chauvinism, national egoism and social imperialism". He went on to compare the invasion of Czechoslovakia to the Americans in the
Vietnam War and more pointedly to the policies of
Adolf Hitler towards Czechoslovakia in 1938 to 1939. Zhou ended his speech with a barely veiled call for the people of Czechoslovakia to wage guerrilla war against the
Red Army. The Chinese historian Li Danhui wrote, "Already in 1968, China began preparations to create a small war on the border." She noted that prior to March 1969, the Chinese troops had twice attempted to provoke a clash along the border, "but the Soviets, feeling weak, did not accept the Chinese challenge and retreated." Another Chinese historian, Yang Kuisong, wrote, "There were already significant preparations in 1968, but the Russians did not come, so the planned ambush was not successful."
Battle of Zhenbao (Damansky) Island against a Chinese fisherman on the Ussuri River, 6 May 1969 On 2 March 1969, a group of
People's Liberation Army troops ambushed Soviet border guards on Zhenbao Island. According to Chinese sources, the Soviets suffered 58 dead and wounded. The Chinese losses were reported as 29 dead. According to Soviet sources, at least 248 Chinese troops were killed on the island and on the frozen river, and 32 Soviet border guards were killed, with 14 wounded. Both sides have since blamed the other for the start of the conflict. However, a scholarly consensus has emerged that the border crisis had been a premeditated act of aggression orchestrated by the Chinese side. The American scholar Lyle J. Goldstein noted that Russian documents released since the
glasnost era paint an unflattering picture of the Red Army command in the Far East with senior generals surprised by the outbreak of the fighting and of Red Army units haphazardly committed to action in a piecemeal style, but all of the documents speak of the Chinese as the aggressors. Most Chinese historians agree that on 2 March 1969, Chinese forces planned and executed an ambush, which took the Soviets completely by surprise. The reasons for the Chinese leadership to opt for such an offensive measure against the Soviets remains a disputed question. According to Robinson, who based his analysis mostly on Soviet sources due to the lack of factual reports from the Chinese at the time of writing, on 2 March around 11:00 Chinese forces ambushed an unsuspecting Soviet border patrol on the island and inflicted heavy losses on the patrol. Shortly, Soviet reinforcements arrived from the nearby outpost and allegedly pinned the Chinese down, surrounded them for a time and then forced the remaining Chinese to retreat to their side of the bank. The entire battle lasted about two hours. Both sides claimed victory, however, neither force remained permanently on the island after the battle was over, although the Soviets periodically moved off and on at will. Robinson wrote that it is not clear who began a battle of 15 March. Both sides claimed that the other side attacked their early-morning patrol. The battle started around 09:45 or 10:00 with artillery fire from the Chinese bank. Initially an outnumbering Chinese force managed to make Soviets to either leave the island entirely or withdraw to its eastern extremity. A consequent counterattack by Russian tanks and mechanized infantry supported by three waves of intense artillery fire at 13:00 apparently broke the Chinese positions on the island and the Chinese retreated to their own bank. The battle was over at 19:00. Soviets did not follow up the Chinese retreat with large-scale garrisoning of the island, although they continued intense patrolling. The Soviets responded with tanks,
armoured personnel carriers (APCs), and artillery bombardment. Over three days, the PLA successfully halted Soviet penetration and eventually evicted all Soviet troops from Zhenbao Island. During the skirmish, the Chinese deployed two reinforced infantry platoons with artillery support. Chinese sources state the Soviets deployed some 60 soldiers and six
BTR-60 amphibious APCs, and in a second attack, some 100 troops backed up by 10 tanks and 14 APCs including artillery. Chinese General
Chen Xilian stated the Chinese had won a clear victory on the battlefield. On 15 March, initial Soviet attacks were repulsed after suffering heavy losses. The Soviet border troops did not fight again, a battalion under Lieutenant Colonel Smirnov from the 135th Motorized Infantry Division went on the attack. The battalion, which came under heavy machine gun fire from the Chinese, sustained heavy losses and withdrew from the island. By the end of 15 March Soviet General Oleg Losik ordered to deploy then-secret
BM-21 "Grad" multiple rocket launchers. The Soviets fired 10,000 artillery rounds in a nine-hour engagement with the Chinese along with 36 sorties. The Chinese troops left their positions on the island, and the Soviets withdrew to their positions on the Russian bank of the Ussuri River. claims that the main group of Chinese troops near the island did not suffer any significant losses as a result of the usage of BM-21 due to a mistake in the calculation by the Headquarters of the Rocket Forces. He claims that after 21:00, the Chinese began firing heavy mortars not only at the island but at the Soviet territory as well and Major V. Nesov, commander of the 135th Motorized Infantry Division, was forced to order the division and frontier guards to retreat 4–5 kilometers inland to avoid casualties. Maxwell notes that much of academic writing about the Zhenbao incident still argues that it resulted from an unprovoked aggressive action by China and that the USSR was unquestionably the victor. On 16 March, the Soviets entered the island to collect their dead, with the Chinese holding their fire. On 17 March, the Soviets tried to recover a disabled
T-62 tank from the island, but their effort was repelled by Chinese artillery. As relations further deteriorated after the battle,
Lin Biao issued Order No. 1 to "strengthen combat readiness to prevent an enemy surprise strike." Among the measures taken, China's three top secret nuclear production plants, which were close to the border with the Soviet Union, relocated to
Third Front areas. Ryabushkin claims that the Soviet border guards had continued to thwart all Chinese attempts to land on it until 10 September when they were ordered to cease fire, effectively surrendering the island, in preparation for the Kosygin-Zhou talks that happened on 11 September. .
Soviet combat heroes Five Soviet soldiers were awarded the top honour of
Hero of the Soviet Union for bravery and valor during the Damansky conflict. Colonel
Demokrat Leonov led the group of four T-62 tanks in a counterattack on 15 March and was killed by a Chinese sniper when he was leaving a destroyed vehicle. Senior Lieutenant Vitaly Bubenin led a relief mission of 23 soldiers from the nearby border guard's outpost and conducted a BTR-60 raid into the Chinese rear that allegedly left 248 attackers dead. Junior Sergeant Yuri Babansky assumed command in a battle on 2 March, when the enemy had a 10–1 superiority, and when Senior Lieutenant Ivan Strelnikov was killed. Babansky later led combat search-and-rescue teams, which retrieved the bodies of Strelnikov and Leonov. Junior Sergeant Vladimir Orekhov took part in the 15 March battle. As a machine gunner, he was part of the first attacking line against the Chinese forces encamped on the island. He destroyed the enemy machine gun nest and was wounded twice, but he continued to fight until he died of his wounds. High military orders of
Lenin, the
Red Banner, the
Red Star and
Glory were awarded to 54 soldiers and officers, and the medals "
For Courage" and "
For Battle Merit" to 94 border guards and servicemen.
Chinese combat heroes During the Zhenbao Island clashes with the Soviet Army in March 1969 one Chinese RPG team, Hua Yujie and his assistant Yu Haichang destroyed four Soviet APCs and achieved more than ten kills. Hua and Yu received the accolade "Combat Hero" from the CMC, and their action was commemorated on a postage stamp. ==Diplomacy==