Stalin and Chiang Kai Shek?

I recently came across two letters Stalin wrote to Chiang Kai Shek in August of 1945.

Thank you for your greetings and for the important support you gave the Soviet Union regarding the defeat of the Japanese aggressors. The surrender of Japan together with Germany has terminated the second World War, and proves that humanity is indebted to the close military co-operation of the Allies for the defeat of the . aggressors in the West and in the East. This victory is of historic and global significance in as much as it is a great, enlightened forward step in the progressive development of humanity.

I express the conviction that the friendship and co-operation of our countries with all freedom-loving nations will serve the cause of universal peace and the prosperity of all peoples.

Thank you for your congratulations on the occasion of the ratification of the Treaty of Friendship and Alliance as well as the agreements between China and the U.S.S.R., signed on August 14.

I am sure that this Treaty and the agreements will provide a solid base for an ultimate development of friendly relations between the U.S.S.R. and China for the well-being and prosperity of our peoples and the reinforcement of peace and security in the Far East and in the whole world.

I beg you, Mr. President,to accept my congratulations on the occasion of the confirmation of these historical documents.

Can anyone explain more of their relation? And how was Chiang Kai Shek portrayed in the Soviet Union in general?

Chiang Kai-shek was viewed as an anti-communist. These letters were written while World War II was still ongoing in Asia. Keep in mind that at this point the CCP and the Guomindang were still somewhat allied against the invading Japanese forces.

It's not much different than, say, Stalin, FDR, and Churchill sending letters to each other praising each others' efforts. If you look at 1941-1946 speeches by any communist leader they'll be full of praise for the "democratic powers" (USA, UK, USSR) who were fighting or had successfully fought fascism.