The Soya straight is the bridge between the Sakhalin island and Hokkaido, the straight which the Soviet Union was going to cross to land a amphibious force on Northern Imperial Japan during the closing days of WWII
As per the Yalta Agreement the Soviet Union joined the war against Japan 3 months after VE day and they took care of much of the Japanese army in Manchruia and stormed to the coast of Japan, re-took Sakhalin and Kuril in the closing hours of the WWII and were planning a full scale amphibious imvasion of Japanese mainland
Operation Olympic and Coronet would see the Americans landing in the South and the Soviets coming from the North, lucky for Japam they surrendered otherwise they probably would have ended up like the Korean peninsula, divided north and south
Anyhow for China to pass through this straight is very good, it's good practice for the commanders and captains to pass through narrow shallow straights it gives them experience and good knowledge, just see the experience a naval captain needs to pass through the Suez canal