One thing not mentioned yet is the Japanese philosophy of bushido (武士道), meaning the "way of the warrior." The classical book on this is Bushido, by Japanese educator Nitobe Inazo. He was a Christian and brilliant, but hugely nationalistic, so that he once said, "I love 2 'J's', Japan and Jesus, and I don't know which I love more." The book was based on the samurai warrior class of feudal Japan, and he painted them as kind of gentleman knights. In reality, though, they were vicious and immoral. I could give many examples, but one is enough. During the war between the samurai forces and the Ainu (the indigenous people of Japan) in the 17th century, the Ainu asked for a peace treaty. The Japanese agreed, and then slaughtered all of the Ainu leaders at the peace conference.
So, these were the guys running WW2 on the Japanese side: a warrior mentality that says never surrender, but commit seppuku first (切腹, otherwise known as harakiri) before the dishonor of surrender. If you are judging Japan in WW2 after American Christian values (surrender to save everyone), you simply do not understand the samurai. Japan refused to surrender until the A-bombs were dropped because of the samurai mentality. Even if defeated by Russia in N. China, they would have fought on literally until the last man in China. The A-bomb and it's absolutely huge destruction finally caused the leadership to overrule the samurai factions, but even then many Japanese warriors wanted to keep fighting.
You have to know, I've witnessed to Japanese WW2 soldiers, and even won one to Christ, Unokatsu, the father of a man in my church. He had fought the Russians in N. China as a machine gunner, and had a very dark place in his heart, telling me he had killed 100's of Russians with his machine gun. Add to these things that I have high rank in both Judo and Karate, and have even trained in jujutsu some. So, I know the samurai mentality well. I firmly believe that it took the A-bomb to defeat them.
Frankly, the Japanese were much better at war than the Russians, and it would have taken much for the Russians to win.