Which Soviet leader's government declared war on Japan on August 8, 1945?

Joseph Stalin's Soviet government declared war on Japan on August 8, 1945.

Soviet Foreign Minister Vyacheslav Molotov delivered the declaration to Japan's ambassador in Moscow. The Soviet government stated that it would consider itself at war with Japan from August 9, and Soviet forces began invading Japanese-held Manchuria shortly after midnight.

The declaration followed secret Allied agreements made at Yalta and came between the American atomic bombings of Hiroshima and Nagasaki. The Soviet offensive rapidly attacked Japanese forces from several directions, including eastern, western, and northern approaches into Manchuria.

Molotov is sometimes given as the answer because he delivered the message, but Stalin was the Soviet leader whose government made the decision. The Soviet entry into the war became one of the major factors in Japan's final surrender decision.