ah peks remarks are insensitive but mean no harm. if WW2 really bother them, suggest they go and hunt down two very old Japanese hanjian among us, one cho boh daily at Istana, the other resides at Oxley Road.
Back then Japan and Germany were the bulwark defense against Soviet Russia expansion in East and West. If Japan collapsed in 1930s via natural disasters, highly likely Soviet Red Army will pour into East Asia, set up satellite states in Korea, Japan and China. Russia will proceed to use "yellow peoples" armies as auxiliary fire against her enemies in Europe - Germany and Britain.
Macro Polo Bridge Incident that started Sino-Japan war was a setup by Chinese Communists and Russia GRU. Many Chinese Commies in 1930s were not under Comintern as they claimed but were directly working for Russia GRU. ( military intelligence )
If I can chose a catastrophe to fall where to "prevent" WW2, it will not be Japan or Germany but Moscow Russia.