Wu and the South

In the times of Zhuge Liang's great northern offensives, the state of Wu had always been on the defensive against invasions from the north. The area around Hefei was the scene of many bitter battles and under constant pressure from Wei after the Battle of Red Cliffs. Warfare had grown so intense that many of the residents chose to migrate and resettle south of the Yangzi. After Zhuge Liang's death, attacks on the Huainan region intensified but nonetheless, Wei could not break through the line of the river defenses erected by Wu, which included the Ruxu fortress.
Sun Quan's long reign is regarded as a time of plenty for his southern state. Migrations from the north and the settlement of the Shanyue increased manpower for agriculture, especially along the lower reaches of the Yangzi and in Kuaiji commandery. River transport blossomed, with the construction of the Zhedong and Jiangnan canals. Trade with Shu flourished, with a huge influx of Shu cotton and the development of celadon and metal industries. Ocean transport was improved to such an extent that sea journeys were made to Manchuria and the island of Taiwan. In the south, Wu merchants reached Linyi (northern Vietnam) and Fu'nan (southern Vietnam). As the economy prospered, so too did the arts and culture. In the Yangzi delta, the first Buddhist influences reached the south from Luoyang.