In early 2009 the joint study group stated that the route would almost certainly begin at Karatsu in Japan's Saga Prefecture and likely travel to Geoje Island on the Korean shore.[1] If the tunnel travels between Karatsu and Geoje, it would span a length of 209 kilometres (130 mi), with an undersea distance of 145 kilometres (90 mi), making it the longest such tunnel in the world.[4]