The Wakhjir Pass, also spelled Vakhjir Pass, is a mountain pass in the Hindu Kush or Pamirs at the eastern end of the Wakhan Corridor, the only potentially navigable pass between Afghanistan and China in the modern era. It links Wakhan in Afghanistan with the Tashkurgan Tajik Autonomous County in Xinjiang, China, at an altitude of , but the pass is not an official border crossing point. With a difference of 3.5 hours, the Afghanistan–China border has the sharpest official change of clocks of any international frontier (UTC+4:30 in Afghanistan to UTC+8, in China). China refers to the pass as South Wakhjir Pass (), as there is a northern pass on the Chinese side. Overview There is no road across the pass. On the Chinese side, the immediate region is only accessible to military personnel. A - long barbed wire fence was erected on the border, and there is a Chinese border guard outpost at Keketuluke just east of the pass. In the summer of 2009, the Chinese Ministry of National Defense began construction of a new road to within of the border for use by border guards. The road leads through the Taghdumbash Pamir to the Karakoram Highway away. The valley to the east of Wakhjir Pass on the Chinese side is the Chalachigu Valley. It is entirely closed to visitors; however, local residents and herders from the area are permitted access. The Chinese refer to it as the portion of Wakhan Corridor in China. On the Afghan side, the nearest road is a rough road to Sarhad-e Wakhan (also known as Sarhad-e Broghil), about from the pass by paths. Just below the pass on the Afghan side is an ice cave, at an altitude of . This is the source of the Wakhjir River, which ultimately flows to the Amu Darya (Oxus). The cave is therefore claimed as a source of the Amu Darya. Dilisang Pass, to Pakistan, is in the same valley about away. History Traditionally, the pass is inaccessible for at least five months out of the year and is accessible irregularly for the remainder of the year. The terrain is extremely difficult, although Aurel Stein reported that the immediate approaches to the pass were "remarkably easy". There are few records of successful crossings by foreigners. Historically, the pass was a trading route between Badakhshan and Yarkand used by merchants from Bajaor. Wakhjir Pass is part