As China, Japan, and South Korea feud over sea and sky, what's underwater is also a matter of contention. Both China and South Korea lay claim to a submerged rock between the countries—one that's the subject of Korean legend. In English, it's called Socotra Rock. Koreans call it Ieodo, while the Chinese know it as the Suyan Rock. China's newly established air-defense zone covers the rock—as does South Korea's planned air-defense zone expansion. China says it "regrets" South Korea's decision to expand, Reuters reports, though a Chinese official says the rock itself doesn't pose a problem: "There currently does not exist a territorial dispute between China and South Korea on this issue."
Still, China said no when Korea asked it to leave Socotra out of its air-defense zone, Quartz notes. The rock sits some 178 miles from China and 92 miles from South Korea. It's 171 miles from Japan, which isn't trying to claim it. All those distances fit within the 230 offshore miles the UN designates as a country's "exclusive economic zone." But the UN also says countries can't claim underwater rocks, and Socotra is 15 feet under the surface. Still, South Korea has a maritime research station positioned on it. Some believe Socotra holds natural gas and mineral resources. Meanwhile, Korean tales hold that dead fishermen's spirits live there, and that if its top is spotted among the waves, there's trouble ahead.