The most common pitfall is to use “Song Dynasty” when you specifically mean the Northern Song. The
宋朝 (Sòng Cháo) lasted for over 300 years, but it's split into two distinct halves:
北宋 (Běi Sòng, 960-1127) and
南宋 (Nán Sòng, 1127-1279). The Northern Song had its capital in the north (Kaifeng) and was wealthier and more innovative. The Southern Song had its capital in the south (Hangzhou) after fleeing an invasion, and it was a period of consolidation and survival. They have different territories, cultures, and historical trajectories.