The so-called "three must caress" means "caressing his ancestors": in recognition of Zheng Chenggong's great deeds of repelling the Dutch. Second, we should be "compassionate": because many people on the island of Taiwan Province Province are mainland immigrants and the two sides of the strait are related by blood, the southeast residents can write to Taiwan Province Province to surrender. Thirdly, it is necessary to "appease those who are most difficult and have to be comforted": that is, to appease Zheng Jing, who may be reduced from a monarch to a prisoner.
The so-called "three must be suppressed" means: first of all, we must "suppress its heart": because Zheng Jing has long been interested in cutting the island for Xinjiang and establishing another dynasty. Second, it is necessary to "destroy its soldiers": because the fighting capacity of Taiwan navy is higher than that of Qing soldiers, it is necessary to strengthen firepower and be cautious. Third, it is necessary to "restrain its land and sea": at that time, many goods in Taiwan Province Province were traded on the mainland, and they were not self-sufficient. So Yao Qisheng suggested cutting off trade, that is, cutting off the back road of Taiwan Province Province.