Liancourt Rocks dispute Japan. In 1954, Japan proposed a reference to the International Court of Justice, which South Korea rejected, believing that the Liancourt Rocks are irrefutably South Korean territories, and thus should not be dealt through diplomatic negotiations or judicial settlement between South Korea and Japan. There are conflicting interpretations about the historical state of sovereignty over the islets. Korean claims are partly based on references to a Korean island called "Usan-do" in various historical records, maps and encyclopedias such as the "Samguk Sagi", "Annals of the Joseon Dynasty", "Dongguk Yeoji Seungnam" (), and "Dongguk munheon bigo" (). According to the Korean
Liancourt Rocks dispute conduct high seas seizure drills. In these circumstances, U.S. ambassador in Tokyo, Tom Schieffer stated "The Ambassador stated the United States understands that Japan is within its rights under international law. The Koreans are behaving irrationally, and the United States is concerned that they may do something crazy, causing a major problem. Everyone needs to back off, he stressed, to enable the matter to be resolved peacefully." In July 2006, the South Korean government sent a research ship to collect data on currents around the Liancourt Rocks and stated "research is just an act based on sovereignty". On July 5,