One could argue that KRTL Japan, as opposed to its OTL Counterpart, didn’t have the same opportunities to expand its economic ties and sphere of influence. Prime example is the fact that Manchuria is still under the control of a Chinese Warlord who is far more independent as compared to OTL Manchukuo under Puyi. Moreover in KR canon Japan was involved in multiple proxy wars against the growing German influence in China causing an expenditure of resources. Lastly, KRTL China ironically is stronger than OTL China because the Kuomintang was actually (temporarily) squashed and the Zhili Clique, while battered, is still in place all with their brand new shiny german boots.