Original 11-dotted line map published by Republic of China in 1947. In 1950s People’s Republic of China removed 2 dotted lines in the area of Gulf of Tonkin after it reached an agreement with Vietnam. Since then map is referred to as 9-dotted/9-dash/U-shaped line.

Source: Wang, K.H. (2010). The ROC’s Maritime Claims and Practices with Special Reference to the South China Sea. Ocean Development & International Law, 41(4), p. 244. doi:10.1080/00908320.2010.499282

Map attached to Chinese note verbale to UN in protest against joint Malaysia-Vietnam submission to Committee on the Limits of Continental Shelf (May 2009)

Source: Dutton, P. (2011). Three Disputes and Three Objectives: China and the South China Sea. Naval War College Review, 64(4), p. 46.