One of the interesting catch phrases during the Sino-Japanese war of 1937-1945 is Quxian jiuguo (曲线救国) or “Saving the nation through twisted means” (In his book The Shanghai Badlands Frederic Wakeman translates it as “Saving the nation in a devious way”, 126). This was the phenomenon of Nationalist military agents or soldiers entering into the collaborationist military or puppet government and secretly continuing to retain contact with Nationalist agents, give them information, or if no contact was maintained, to at least engage in anti-Communist suppression while they served in the puppet government and the occupying forces of the Japanese. Sometimes those who claimed to be doing 曲线救国 were not in fact connected to the Nationalists in any way before they surrendered to or joined the puppet institutions.
When the war was over and many of the puppet officials were tried in the treason (汉奸) trials after the war those with any considerable power would invariably claim that they were trying to save the nation indirectly through their anti-communist activities or by feeding the Nationalists information. We have some evidence to show this kind of contact between the agents of puppet regime of Wang Jingwei or the various puppet military units and the intelligence services of the Nationalists (Juntong) and its ruthless leader Dai Li, but some of those who made this claim (such as Chu Minyi 褚民谊) may have been executed quicker to prevent the embarrassing revelation of ongoing contact and peace negotiation efforts between the Nationalists and the puppet government from getting out. A lot of these claims are far from conclusively proven but serve as great conspiracy material.
I’m now reading 刘熙明’s book on the puppet military or 伪军 and he talks quite a bit about the phenomenon of 曲线救国 for those in the military. He argues that there was a Communist equivalent and says there is reason to believe that the CCP also occasionally tolerated the surrender of some of their units to the Japanese and their conversion into puppet troops as long as they continued to serve them indirectly. For these semi-traitors they used the term 白皮红心 or “white skin and red heart” (Fascist or reactionary on the outside but a Communist at heart). (102)
刘熙明 (Liu Ximing) also listed (103) a wonderful collection of some of the idioms that the Nationalist military and government allegedly used to indicate that surrender to the Japanese while shameful, was still better than to give up the fight against the Communists. Here are a few that he has dug up: 反共第一，抗战第二 First: The fight against Communism, Second: the war of resistance 宁亡与日，勿亡与共 Never lose to the Communists, lose rather to the Japanese 日可以不打，共不可不打 It is acceptable to not attack the Japanese, but unforgivable to not attack the Communists 变匪区为沦陷区 Turn a district plagued by [Communist] bandits into a [Japanese] occupied territory 宁可让给敌人，不可让给匪军 Never give up to the bandit [Communist] forces, it is better to give up to the [Japanese] enemy. 宁投日本人，不投八路军 Never surrender to the [Communist] 8th Army, surrender rather to the Japanese.
He doesn’t say if any of these were widespread, indeed it is possible that some of these are fabrications created by Communist propaganda. Though Liu Ximing is a scholar working out of Taiwan, at least some of his footnotes (104) for these lines are from mainland China sources (for example Shandong provincial party archives and Jiangsu Wenshi ziliao).