Yi I’s Seonghak jipyo

Yi I presented to King Seonjo the Seonghak jipyo (Essentials of Sage Learning), summarising Neo-Confucianism and the learning of kings.

Stressing the workings of material force (gi), Yi I held that only gi issues forth while principle rides upon it, and that principle is universal while gi is particular. He also pressed for practical reform: in 1569 he set out the ideal of kingly rule and proposals for reform in the dialogue Dongho mundap, and to remedy the abuses of the tribute tax he called for collecting tribute in rice (sumibeop).

Presented in 1575, the Seonghak jipyo held that wise ministers must teach and guide the ruler to achieve sage learning, arranging the essentials of the classics under self-cultivation, ordering the family and governing. He also wrote the primer Gyeongmong yogyeol and drew up the Haeju community compact. His school passed to the Giho school of Jo Heon, Kim Jang-saeng and others.