Shaan–Gan–Ning Border Region, or in postal romanization Shen–Kan–Ning, commonly known by its historical sources as the Yan'an Soviet was a historical proto-state that was formed in 1937 by the Chinese Communist Party following the collapse of the Chinese Soviet Republic in agreement with the Kuomintang as a part of the Second United Front policy, substituting the former anti-Kuomintang Soviets. Wikipedia