Why was Japan not happy with the Paris Peace Conference?

Answer 1

Despite gaining territory within China and islands within the Pacific Ocean, these areas were mandated under the League of Nations(so not fully under their control). Added to this, a racial equality clause was not included in the legal framework for the League of Nations. There was general dissatisfaction with the Paris Peace Conference across East Asia. Notably, Korea thought they may gain self-determination (as espoused by Wilson) but they continued to be under Japanese control, the led to riots and suppression. China were angered that Shandong province was moved from German to Japanese control. Although Japan fared better than China and Korea they still felt like an unequal member of the so-called 'imperialist club'.