Taiwan was Xi’s overriding focus. While Xi didn’t name Japan or ask Trump to pressure Tokyo directly, the people said, his discussion of the post-World War II order was an implicit reference to Japan as the losing party, showing the depth of his concern over the recent tensions.

Chinese leader Xi Jinping was angry, and President Trump was listening.

The China-Japan feud over Taiwan has started taking a cultural toll after Chinese authorities cancelled several concerts and performances featuring Japanese artists and Chinese cruise operators have b...