pipeline that would come from Russia and pass through North Korea. In June 2018, president Moon Jae-in became the first South Korean leader to speak in the Russian Parliament. On 22 June, Moon Jae-in and Putin signed a document for foundation of free trade area. Japan Korea and Japan have had difficult relations since ancient times, but also significant cultural exchange, with Korea acting as the gateway between East Asia and Japan. Contemporary perceptions of Japan are still largely defined by Japan's 35 year colonization of Korea in the 20th century, which is generally regarded in South Korea as having been very negative. Japan is today South Korea's third largest trading partner, with 12% ($46 billion) of exports in 2016. There were no formal diplomatic ties between South Korea and Japan directly after independence the end of World War II in 1945. South Korea and Japan eventually signed the Treaty on Basic Relations between Japan and the Republic of Korea in 1965 to establish diplomatic ties. There is heavy anti-Japanese sentiment in South Korea because of a number of unsettled Japanese-Korean disputes, many of which stem from the period of Japanese occupation after the Japanese annexation of Korea. During World War II, more than 100,000 Koreans served in the Imperial Japanese Army. Korean women were coerced and forced to serve the Imperial Japanese Army as sexual slaves, called comfort women, in both Korea and throughout the Japanese war fronts. Longstanding issues such as Japanese war crimes against Korean civilians, the negationist re-writing of Japanese textbooks relating Japanese atrocities during World War II, the territorial disputes over the Liancourt Rocks, known in South Korea as "Dokdo" and in Japan as "Takeshima", and visits by Japanese politicians to the Yasukuni Shrine, honoring Japanese people (civilians and military) killed during the war continue to trouble Korean-Japanese relations. The Liancourt Rocks were the first Korean territories to be forcibly colonized by Japan in 1905. Although it was again returned to Korea along with the rest of its territory in 1951 with the signing of the Treaty of San Francisco, Japan does not recant on its claims that the Liancourt Rocks are Japanese territory. In response to then-Prime Minister Junichiro Koizumi's visits to the Yasukuni Shrine, former President Roh Moo-hyun suspended all summit talks between South Korea and Japan in 2009. A summit between the nations' leaders was eventually held on 9 February 2018 during