Research into current hostility between Sino Japanese

what was the cause of current conflict and hostility between japan and china ,but not between south korea and china and japan and south korea. im reading history to. understand the geopolitical hostility between China and japan the root cause was the Japanes militaryy occupation and massacre of chinese for which the right wing nationalsts enshrine as war heros,the propaganda by japanese textbook to downplay the severity of war crimes in the early 20th century,many young chinese students went to japan to study and lived there.reformers like chiang kai shek and sun yat sen lived and studied in japan. there they were exposed to modernisation of meiji reformers.