Did the 1968 incident actually happened, if so why did it take 1 year for the PLA to retaliate? Why is there no diplomacy in this issue?On January 5, 1968, the Soviet army crushed and killed four Chinese with armored vehicles. This is the earliest trigger of the incident.
In March 1969, PLA ambushed the Soviet army.
Why did the PLA have to invade Soviet island to ambush Soviet troops?
Who were the chinese killed?