<P> The nine - dash line was originally an "eleven - dashed - line," first indicated by the then Kuomintang government of the Republic of China in 1947, for its claims to the South China Sea . After, the Communist Party of China took over mainland China and formed the People's Republic of China in 1949 . The line was adopted and revised to nine dashes / dots as endorsed by Zhou Enlai . </P> <P> The legacy of the nine - dash line is viewed by some PRC government officials, and by the PRC military, as providing historical support for their claims to the South China Sea . </P> <P> In the 1970s, however, the Philippines, Malaysia and other countries began referring to the Spratly Islands as included in their own territory . On 11 June 1978, President Ferdinand Marcos of the Philippines issued Presidential decree No. 1596, declaring the north - western part of the Spratly Islands (referred to therein as the Kalayaan Island Group) as Philippine territory . </P> <P> The once abundant fishing opportunities within the region are another motivation for claims . In 1988, the South China Sea was believed to have accounted for 8% of world fishing catches, a figure that has grown since then . There have been many clashes in the Philippines with foreign fishing vessels (including those of the PRC) in disputed areas . The PRC believes that the value in fishing and oil from the sea has risen to a trillion dollars . </P>

Declaration on the conduct of parties in the south china sea wiki