Song entered Yuan Shikai's New Army as an officer in training upon graduation from military institute during the regency of Empress Dowager Cixi[?]. As his superior Feng Yuxiang[?] participated the Northern Expedition, he assumed the head of 4th division and Chairman of Shanxi province.
Switching side to Kuomintang after the abortive coup d'etat in 1930 of Feng against Chiang Kai-shek, his troops were assigned as 24th Army and garrisoned in southern Shanxi province where he is responsible for the frontiers of the Rehe and Chahar provinces against the Japanese Manchukuo.
Song was the chairman of Chahar province when Japan invaded the provinces in the end of year 1932. Though equipped only with obsolete rifles, spears and sabres compared to the better armed Japanese, Song led the 24th army to resist the aggression in a war known as the War at the Great Wall[?] (proper translation? 熱河長城之戰). Japanese troops then entered the suburbs of Beijing and Tianjin after the predictable victory. Song was relieved from post but reinstalled as commander after the Ho-Umemura Agreement[?].
In the Battle of Lugou Bridge, his 24th Army bore the blunt of Japanese Guandong Army. His troops were halved after the defeat and chased by the Japanese into Shandong Province. However Han Fuqu[?], chairman of the province and suspected for his clandestine collaboration, forbade Song to retreat across Huang he where the 24th Army was shattered at Dezhou[?].
need more info of his role in subsequent battles in Sino-Japanese War (1937-1945)