Professor Schwiedrzik's script (distribution limited to Viennese university students), elaborates that during the northern expedition two factions formed within the GuoMinDang in 1927. The left one was influenced by Borodin, the Russian adviser. It wanted to attack Beijing early on. The right one, Chiang Kaishek and his supporters, wanted to take Shanghai first.
The script repeatedly states the right group wanted to solve the "social problem" first, while the left group wanted to achieve national unification by sacking the capital.
I have searched my textbook and tried hard to find resources online, but I have no idea what "social problem" was to be remedied by taking Shanghai. I am hoping for your support.
In the accounts that I am familiar with, a split between left and right is pictured after the incident/massacre at Shanghai. But this script mentions a split even before and a "social problem" I can't find anything about.
Furthermore, it doesn't appear like social problems were Chiangs main concern at all. As far as I gather, he was greatly aided in taking Shanghai by a communist uprising. But as soon as the city was taken he started a purge of the communists and allied with those who thought their demands were extreme!