There was never an invasion threat posed by Russia to Japan; their entire army, minus a few garrison troops was still in Europe, consolidating it’s stranglehold over Eastern Europe and maintaining a threat faced toward the western allies.

I disagree, they know what was being discussed by the Emperor and the Generals, but there are several areas where scholars differ.

From the net sifter:

Prior to the Japanese surrender in August 1945, the Soviet Red Army was secretly massed along the borders of the Far East, specifically in Eastern Siberia, the Russian Far East, and Outer Mongolia. Following the defeat of Nazi Germany, Stalin shifted over 1.5 million troops to this region to prepare for a massive invasion. On August 9, 1945, the Soviet Union declared war on Japan and immediately launched the Soviet Invasion of Manchuria.

Prior to and during the surrender process, the Red Army was positioned across several occupied and contested territories:
Manchuria (Northeast China): Overran the Japanese Kwantung Army and occupied the territory.
Inner Mongolia: Pushed into the Japanese-controlled Mengjiang puppet state.
Korea: Landed amphibious assaults and occupied the northern half of the Korean Peninsula at the 38th parallel.
Sakhalin and the Kuril Islands: Invaded and occupied these Japanese prefectures in the final days of the war.

And on discussions- net sifter:

The Soviet Invasion and Shift

Any remaining delusions vanished in August 1945.

August 8/9: The Soviet Union declared war on Japan and launched a massive invasion of Japanese-held Manchuria.

The Impact: This shattered the Japanese "peace faction's" hopes of Soviet mediation and sparked deep fear among the generals that the Soviets would occupy Japanese territory and potentially abolish the imperial institution.

The Surrender Decision: Faced with the Soviet invasion, the atomic bombings, and the impending collapse of the Japanese military, Emperor Hirohito intervened to accept the Potsdam Declaration and surrender to the United States, determining that the Western Allies would be more likely to preserve the imperial throne than a communist Soviet Union.