Tense relations between the two countries heated up Friday, when Chinese officials denounced statements by Japanese premier Shinzo Abe comparing China's actions in the disputed East and South China Seas to Russia's offensive in the Crimean peninsula. Chinese claims over territories in the disputed waters have caused friction not only with Japan, but also with Vietnam and the Philippines.
Background:
China angrily denounces Japan for Crimea-Russia analogy [Reuters]
Japan and China take regional spat to world stage [Blouin Beat]