I think about 50% Japanese cultures came from China, the rest are Indigenous. They have their own mythology, religion Shinto and martial tradition Bushido. They only selectively learn Chinese philosophies and cultures. For example, Japs never learn and value the first attribute of Confucianism humane benevolence, but emphasize other Confucian qualities such as loyalty, courage and knowledge. So, Japs are incomplete Confucians and can be said never truly absorbed the essence of Chinese wisdoms in some sense. That explains why the Jap Army collectively behaved such savagely in WW II and others wars in China.
Evan to this day, Japs have the weird logic and understandings about China as explained by the Chinese professor in the following clip. They pretty much live in a cocoon society with filtered info. Never take the Jap threat lightly esp when they have massive offensive capabilities because they will attack China according to their logic.