September 3rd is Victory Day against Japan of China and Russia.
This day commemorates the victory of the Allies in World War II over the Empire of Japan.
In Japan, August 15th, “Potsdam Declaration” was issued on, is celebrated as this anniversary.
But in China and the Soviet Union (now Russia), September 3rd is the anniversary of victory against Japan in the war.
Victory Day of the other Allied countries against Japan is September 2nd, the day before.
・References
– https://tama.wtf/jp/society/today/victory-over-japan-day-in-china-and-russia
– The National WWII Museum: V-J Day