Chen Duxiu was one of the founders of the Communist Party of China in 1921. In 1926, the publication of “An Analysis of Classes in Chinese Society” by Mao Zedong  challenged key tenets about traditional revolutionary strategy, triggering a leadership contest. Chen lost this contest, and was subsequently expelled from the Party in 1927. Throughout this period and beyond, Lu Xun was an important literary figure with avowed, openly-revolutionary political commitments. 
In 1936 Chen wrote a private letter to Lu Xun trying to gain his support, arguing like Trotskyists often do — highlighting the opportunism of the “practical compromises” made by those in power, flattering the idiosyncracy of his would-be ally, etc.:
“The Chinese Communists took to military adventurism. Abandoning work in the cities, they ordered Party members to rise everywhere although the tide of revolution had ebbed, hoping to make Reds out of the peasants to conquer the country. […] We were against the opportunist and reckless policies and bureaucratic party system of the Stalinists. […] For the last decade and more, sir, I have admired your scholarship, writing and moral integrity, […] you alone have fought on without respite to express your own views.”
What follows is Lu Xun’s reply, made in public rather than delivered privately.
The Communist Party of China would go on to emerge victorious in 1949, having made “Reds out of the peasants.”
Dear Mr. Chen,
I have received your letter and the copies of Struggle and Spark which you sent me.
I take it that the main drift of your letter is contained in these two points: You consider Stalin and his colleagues bureaucrats, and the proposal of Mao Zedong and others — “Let all parties unite to resist Japan” — as a betrayal of the cause of revolution.
I certainly find this “confusing.”  For do not all the successes of Stalin’s Union of Soviet Socialist Republics show the pitifulness of Trotsky’s exile, wanderings and failure which “forced” him in his old age to take money from the enemy? His conditions as an exile now must be rather different from conditions in Siberia before the revolution, for at that time I doubt if anyone so much as offered the prisoners a piece of bread. He may not feel so good, though, because now the Soviet Union has triumphed. Facts are stronger than rhetoric; and no one expected such pitiless irony. Your “theory” is certainly much loftier than that of Mao Zedong; yours is high in the sky, while his is down-to-earth. But admirable as is such loftiness, it will unfortunately be just the thing welcomed by the Japanese aggressors. Hence I fear that it will drop down from the sky, and when it does it may land on the filthiest place on earth.
Since the Japanese welcome your lofty theories, I cannot help feeling concern for you when I see your well-printed publications. If someone deliberately spreads a malicious rumour to discredit you, accusing you of accepting money for these publications from the Japanese, how are you to clear yourselves? I say this not to retaliate because some of you formerly joined certain others to accuse me of accepting Russian roubles. No, I would not stoop so low, and I do not believe that you could stoop so low as to take money from the Japanese to attack the proposal of Mao Zedong and others to unite against Japan. No, this you could not do. But I want to warn you that your lofty theory will not be welcomed by the Chinese people, and that your behaviour runs counter to present-day Chinese people’s standards of morality. This is all I have to say about your views.
In conclusion, this sudden receipt of a letter and periodicals from you has made me rather uncomfortable. There must be some reason for it. It must be because some of my “comrades-in-arms” have been accusing me of certain faults. But whatever my faults, I am convinced that my views are quite different from yours. I count it an honour to have as my comrades those who are now doing solid work, treading firmly on the ground, fighting and shedding their blood in the defence of the Chinese people. Excuse me for making this an open reply, but since more than three days have passed you will probably not be going to that address for my answer.
 Some useful dates: Chen Duxiu (b. 1879-1942), Mao Zedong (b. 1893-1976), Lu Xun (b. 1881-1936). — R. D.
 The reference is to Chen’s argument that “Chinese Communists who blindly take orders from the Moscow bureaucrats [have] confused the people’s mind, making the masses believe that all those bureaucrats, politicians and executioners are national revolutionaries who will resist Japan too.” — R. D.