The 60-year-old dispute over the islands, annexed to the Soviet Union at the end of the Second World War, has prevented Russia and Japan from signing a peace treaty that would formally end their WWII hostilities, and has been a major obstacle to closer cooperation between the two nations in areas such as energy.
Addressing parliament Wednesday, Aso said Japan would receive more territory if the islands were split by total area rather than divided by number, with the two southernmost islands going to Tokyo and the two others to Moscow. If the former scheme is used, Japan will regain three of the islands and a quarter of the largest, northernmost island, Etorofu.
But in a statement issued Thursday, the Foreign Ministry said Aso's suggestion should not be viewed as an official proposal on the part of the Japanese government, but only as a display of its willingness to resolve the territorial dispute sooner rather than later.
Tokyo has long maintained that all the four islands should be returned to Japan, and analysts say the government is unlikely to accept the idea of having Russia retain control over 75% of Etorofu.
Speaking to RIA Novosti on condition of anonymity, a source in Japan's ruling Liberal Democratic Party said Aso's proposal was made in line with Tokyo's overall goal of reaching a mutually acceptable solution to the territorial dispute and signing a peace deal with Russia. He said the government is now facing strong criticism from the opposition for lack of progress in that area.
The source also said it was highly unlikely that Prime Minister Shinzo Abe knew of Aso's proposal in advance, but that on the whole, he was quite supportive of the minister's quest for new solutions, however eccentric some of them may appear. Negotiations over the Kurils have now reached a deadlock, and the need to search for ways out of it is all too obvious, he added.
Aso said Japan should try to overcome the impasse over the Kurils before the end of Russian President Vladimir Putin's term in office in 2008, given the incumbent's strong political positions and his willingness to resolve the dispute.