RUSSIA-JAPAN TERRITORIAL CONFLICT

In April 1941 [two months prior to 'Operation Barbarossa'] Russia cunningly
neutralized the military threat from the East by means of signing a Neutrality Pact with Japan. Thus when the Wehrmacht swept into Russia, Hitler was unable to mobilize a Japanese attack against Russia's rear, despite the provisions of the 1936 Anti-Comintern Pact &

1940 Axis Powers Tripartite Pact.
Nonetheless, when Japan opened its campaign of aggression against the USA and Britain
in the Pacific and Far East, Hitler & Mussolini gratuitously honored the Pacts by declaring war on the USA [four days after Pearl Harbor December 7, 1941]!

After cessation of hostilities in Europe in May 1945, the Western Allies were still
engaged in the Far East and US Forces were still far from realizing a successful invasion of the Japanese mainland.
However for the Russians to leap onto Japanese soil was physically easy:
indeed the total occupation of Japan was such a tempting prize that moves indicating imminent abrogation of its Neutrality Pact were discerned in the summer of 1945 - prior to
the bombing of Hiroshima on August 6.
Indeed history records that Russian forces commenced their occupation and ethnic cleansing of Japanese territories on August 8 1945 - refusing to restore the status quo ante to this day!

The atom bombing of Nagasaki the following day - which brought about Japan's acceptance of surrender terms on August 14 and landing of US forces on mainland Japan on August 26 -
also constituted a warning to Russia not to progress further with its unprovoked aggression against a defeated Japan!
On September 2, 1945, the USS Missouri anchored in Tokyo Bay, aboard which the Japanese signed the formal terms of their surrender to the United States of America.
Thus were the Japanese spared decades of the fate rendered by Russia to

nations of Eastern Europe.