Japan The Kanchazu Island incident (乾岔子島事件, Kanchazutō jiken) occurred in late June 1937 on the Amur River, at the Soviet–Manchukuo border.

On June 19, two Soviet motorboats crossed the center line of the river, unloaded 20 troops, and occupied Kanchazu Island.

On 29 June, a planned operation by the Imperial Japanese Army's 1st Division headquarters was approved for a night attack on Kanchazu for the expulsion of Soviet troops from the island.

On the morning of June 30, Japanese soldiers from the 49th Regiment of the 1st Division led by Colonel Mihara Kanae launched a prolonged attack against the Soviets.

The Japanese soldiers proceeded to set up hastily-improvised firing sites, and they loaded their guns with both high-explosive and armor-piercing shells.