The People's Liberation Army Navy (PLAN), also known as the PLA Navy, is the naval warfare branch of the People's Liberation Army, the national armed forces of the People's Republic of China. The PLAN can trace its lineage to naval units fighting during the Chinese Civil War and was established in September 1950. Throughout the 1950s and early 1960s the Soviet Union provided assistance to the PLAN in the form of naval advisers and export of equipment and technology. Until the late 1980s, the PLAN was largely a riverine and littoral force (brown-water navy). However, by the 1990s, following the fall of the Soviet Union and a shift towards a more forward-oriented foreign and security policy, the leaders of the Chinese military were freed from worrying over land border disputes, and instead turned their attention towards the seas. This led to the development of the People's Liberation Army Navy into a green-water navy by 2009. Before the 1990s the PLAN had traditionally played a subordinate role to the People's Liberation Army Ground Force.