China has just delivered its most punishing blow yet in the escalating Tokyo–Beijing showdown. Weeks after Japanese PM Sanae Takaichi’s Taiwan warning enraged Beijing, China reinstated a full-scale ban on Japanese seafood — a move that threatens billions in exports and strikes at the heart of Japan’s coastal economy. Travel warnings, mass cancellations, and diplomatic fury now pile onto an already fragile relationship. But behind this sudden economic assault lies a deeper strategic message from Beijing.