President Xi Jinping spoke on the phone with US President Donald Trump — their first call after the Busan meeting. According to the Chinese Ministry of Foreign Affairs, the call was initiated by the US side. And at the very top of the agenda? The Taiwan question.

Xi reiterated China's principled stance on the Taiwan question, stressing that Taiwan's return to China is a key part of the postwar international order. Trump said the US acknowledges the significant role China played in the victory in World War II and understands the importance of the Taiwan question to China.

The timing matters. With Japan hyping up a so-called "Taiwan contingency", this direct talk sends a powerful message — to Japan, and to separatists — that miscalculation will not be allowed.