Japan's tense relations with South Korea took a turn for the worse yesterday, when a fleet of Korean trawlers defied warnings and began fishing in disputed waters claimed by Tokyo.
The Korean boats are operating off the Russian-controlled Kurile Islands, which have been the subject of a territorial dispute since they were seized by the Soviet Union after the Second World War. South Korea's decision to send the boats despite protests from Japan marks the latest deterioration in a difficult relationship between the neighbours.
The approach of next year's football World Cup, which will be hosted by the two countries, brought hope that South Korea's traditional suspicion of Japan was beginning to abate. But in the past four months, relations have sunk to their lowest point for several years.
In April, Seoul temporarily recalled its ambassador when Japan licensed a history textbook that Korea accuses of glossing over wartime atrocities. The Koreans have been infuriated further by a declaration by theJapanese Prime Minister, Junichiro Koizumi, that he will visit the Yasukuni Shrine, which honours Japan's war dead and included executed war criminals.
Perceptions of the war are deeply controversial in Korea, which was ruled as a Japanese colony for 35 years. Last month, Korea suspended military co-operation with the Japanese, and a group of Japanese MPs visiting Seoul were snubbed by their Korean counterparts.
The Koreans came to a deal with the Russian authorities on the Kuriles last year, but the decision to press ahead with the fishing in the face of Japanese protests is a sign of the breakdown in co-operation between Tokyo and Seoul.
The Kurile Islands, or the Northern Territories as they are known in Japan, are the southern links on a necklace of islands connecting the northern Japanese island of Hokkaido with the Kamchatka Peninsula in the Russian far east. Russia seized them after the Japanese surrender in August 1945, an act of opportunism that Japan has never forgiven.
The 26 Korean boats, which are planning to take 15,000 tons of a fish known as the Pacific saury, began their fishing last night off the Russian-occupied island of Shikotan. Japanese and Korean diplomats held unsuccessful talks in Tokyo over the weekend.
Both countries emphasise that the dispute must be resolved peacefully. Japan's Foreign Minister, Makiko Tanaka, is expected to send a letter of protest. Tokyo will also retaliate by banning Korean saury fishermen from waters off north-eastern Japan.
Japanese-Korean relations have deteriorated since the election of Mr Koizumi in April. Within Japan, his plans for economic restructuring mark him as a radical, but in Asia, especially among countries that suffered under Japan's wartime military, he is regarded as a dangerous nationalist.
China and South Korea have been angered by his refusal to order changes to the historytextbook, whichmakes no reference to the Japanese army's use of sex slaves known as "comfort women" or to Unit 731, the experimental project that tested biological weapons on live prisoners-of-war.
Mr Koizumi has shown signs of wavering over his planned visit to Yasukuni Shrine on 15 August, the anniversary of Japan's surrender in 1945. On Monday he said: "Diplomatic relations with China and South Korea are very important. In Japan, we have our own ways of paying our respects."