According to professor Park Jin-hee of the Korea Maritime University, in the period before 2007 it cost $665 to ship a 6 metres (20 ft) container from Osaka to Busan.[35] With an undersea tunnel, the estimated price would drop to $472, a saving of almost 30%.[2] Further economic benefits would be gained if North Korea would permit trains to cross through it into China, from where trains could then access the Trans-Chinese Railway to the Trans-Siberian Railway to Europe.[3][4][5] An additional proposal raised in 2009 suggested the construction of a second tunnel from Pyeongtaek at the north end of South Korea, tunneling westward to Weihai in China's Shandong Province, completely bypassing North Korea, whose government has been seen as volatile and temperamental.[33] Such a Yellow Sea tunnel would cover a distance of 370 kilometres (230 mi).[37]