The Soviet Union's strong local but weak oceanic amphibious capability

How capable was the Soviet Union at amphibious operations, and did that threat affect Japan's surrender?

It was effective in local seas but lacked oceanic reach; the greater pressure on Japan came from Soviet attacks trapping forces in China and Manchuria.

Soviet forces had substantial experience with amphibious operations in the Black Sea, Baltic, and Far East. Their strength lay in these regional operations, with much less capacity for an oceanic assault. Soviet intervention in 1945 threatened Japan's hope of moving troops from its relatively untouched armies in China back to defend Japan. Once Soviet forces attacked Japanese-held territory in China, those troops became unavailable for the intended transfer. This is presented as one factor in Japan's surrender decision, without assigning it sole responsibility.