In the early morning hours of 2 March 1969, Soviet border security personnel spotted a platoon-sized element of Chinese soldiers crossing the frozen Ussuri River, which forms a natural boundary between China and the USSR. The Soviet border outpost situated on the Ussuri launched a small contingent to intercept the Chinese element. Up to that point of time, these occurrences were fairly common. Both Soviet and Chinese troops would conduct patrols on many of the small islands (the majority of these islands were disputed territory between the two sides) and small skirmishes would occur. Up to this point, these clashes typically consisted of shouting matches and occasional fistfights. .
This particular day, however, hostilities were escalated significantly. The Chinese troops set up positions on Zhenbao Island and when the Soviet soldiers were within 100 meters of their position, they opened fire with machine guns and small arms fire, killing seven Soviets during the initial volley. The battle would last upwards of two hours and resulted in thirty-one Soviet troops killed in action (KIA), fourteen wounded in action (WIA) and an unknown number of Chinese casualties. This battle on Zhenbao Island, and subsequent larger scale border clashes, sparked an already strained relationship between the two powerful nuclear-armed nations. The escalations of force between the two states held the distinct possibility of an all-out nuclear weapons confrontation. .
At the time, China possessed only a fraction of nuclear weapons in their arsenal and first tested their nuclear weapons only five years prior to the Zhenbao Island incident. The Soviets, however, had amassed a massive and diverse stockpile of nuclear weapons. Not only did they hold many more nuclear warheads, their weapons delivery systems were much more developed compared to the Chinese. Immediately after the initial armed conflict on Zhenbao Island, Soviet Premier Alexei Kosygin and Soviet leader Leonid Brezhnev enacted an aggressive diplomacy strategy formulated to reach a peaceful accord with Mao Zedong and the Chinese.
