There are conflicting interpretations about the state of sovereignty over the islands in pre-modern times. A Korean claim is partly based on references to a Korean islands called Usan-do in various historical records and maps. According to the Korean view, these refer to today's Liancourt Rocks, while the Japanese side argues that they must refer to a different island, today called Jukdo, a small islet located in the immediate vicinity of the nearest larger Korean island Ulleung-do.
Japan officially incorporated the islands as part of its territory in 1905, shortly before it occupied Korea itself as a protectorate.
The present-day conflict largely stems from conflicting interpretations of whether Japan's renunciation of sovereignty over its occupied territories after the Second World War was supposed to cover the Liancourt Rocks too. A decision by the Supreme Command of the Allied occupation powers (SCAP), Instruction #677 of January 29, 1946, listed the Liancourt Rocks as part of those territories over which Japanese sovereignty was to be suspended, but the final peace treaty between Japan and the Allied powers, the Treaty of San Francisco, did not mention them.
Maybe the above was the only way for Wikipedia to deal with the problem of people always changing the history section to suit their biased views of history, but it means the dictionary has decided not to talk about the history. Unfortunately, the references it used for the article almost all point to Korean sites, which do distort the history of the islets.