In episode 31 of Giant (aired on August 31st), Jo Pil Yun told Sung Mo that he read many history books in the prison cell and he is going to use one of the tactics from them to get Manbo Construction Company. He told Sung Mo that tactic is “이이제이” (yi-yi-je-yi) – 以夷制夷. That is one of the four letter Chinese phrases meaning “barbarians were defeated by barbarians.” Jo Pil Yun means he is going to use Han Gang Construction Company to make Manbo Construction Company his own.
이이제이 (yi-yi-je-yi) is one of the war tactics from a famous Chinese book, Three Kingdom. One of the kings, Jo Jo, defeated his two enemies, Yoo Bi and Yu Po, with this tactic. He drove Yoo Bi and Yu Po to fight each other and defeated both of them when they were weakened.
In this drama, Jo Pil Yun gave Han Gang Construction Company a permit to build its apartment on purpose, to make Gang Mo and Jung Yun to fight each other and he is trying to take advantage from that.