 It is not known what criteria were used to determine who would stay and who would go, but 16,000 troops and some of the Communists' most notable commanders at the time (including Xiang Ying, Chen Yi, Tan Zhenlin, and Qu Qiubai) were left to form a rear guard to divert the main force of Nationalist troops from noticing the Communists' general withdrawal.The withdrawal of 84,000 soldiers and civilians began in early October 1934.Zhou's intelligence agents were successful in identifying a large section of Chiang's blockhouse lines that were manned by troops under General Chen Jitang, a Guangdong warlord who Zhou identified as being likely to prefer preserving the strength of his troops over fighting.