In 1924,according to Taylor, Vasily Blucher "commander of Soviet Eastern forces,whom [Chiang] had met in Siberia and immediately liked,arrived to serve as his chief of staff..".
http://en.wikipedia.org/wiki/Vasily_Bl%C3%BCcher
Photo One--1926,Blucher third from right,Chiang second from rightFrom 1924 to 1927 Blücher was a Soviet military adviser in China, where he used the name Galen(after the name of his wife, Galina) while attached to Chiang Kai-Shek's military headquarters. He was responsible for the military planning of the Northern Expedition which began the Kuomintang unification of China. Among those he instructed in this period was Lin Biao, later a leading figure in the Chinese Peoples Liberation Army.
Photo Two--1926,"Chiang with General Blucher and other senior Soviet military advisers..Northern Expedition.."