 Self-enrichment was relatively secure through the illicit but uncontrollable opium trade; survival entailed maintaining troops but using them as little as possible.In this, the territory of Xikang province was advantageous to Liu, since its marginal position effectively insulated him from rival warlords, and from military engagements ordered by the central government.During the pursuit of the communist forces during the Long March, this conflict between the two leaders came to a head.