Zengmu shoal is underwater, but it is not exposed to the sea. However, China claims to be a territory, and the Japanese Okinawa Reef emerges from the sea, but China insists that it is a reef.

Let's put it this way: Zengmu shoal is the southernmost tip of the South China Sea in China. China takes Zengmu shoal as the boundary, not to delimit another 200-nautical-mile exclusive economic zone, but to show that the boundary of China sea area ends here, and Zengmu shoal is equivalent to a boundary pillar. Japan regards Okinawa Reef as an island to delimit the exclusive economic zone of a larger sea area.