I have read a couple of books by Japanese pilots. One by Saburo Sakai and another by a torpedo bomber pilot. Both tell of extremely tough training and very high washout rate.
After the war heated up they quit it but too late. I think they really were great pilots but also think they understated Japanese brutality. Also read that no one believes Sakai really shot down 60 planes, but he may have really thought he did.
The Japanese Zeroes brutalized the Buffaloes, Airacobras and Hurricanes (and Spitfires) early in the war. Also many of the Zeroes kills were against hopeless Chinese pilots and aircraft. So 60 kills for Sakai is not impossible. German Aces sometimes had 300 or more kills. Neither AirForce rotated their pilots out of combat. They flew til they died. So big scores were likely.