The Chinese People's Liberation Army Fourth Field Army was an army group-level military formation of the People's Liberation Army. It was formed during the Chinese Civil War by existing members of Eighth Route Army and New Fourth Army stationed in Manchuria along with others, where they fought against the Republic of China government. The army also incorporated elements of the former Manchurian occupation forces, which included around 30 thousand Japanese technicians. The army was commanded by Lin Biao, and it was involved in many crucial battles including the Liaoshen Campaign.