8 6 1 ▁as ▁" the ▁ 2 3 4 th ▁year ▁of ▁Ch ong z hen ." ▁ ▁Late ▁Jose on ▁period ▁ ▁Emer gence ▁of ▁Sil h ak ▁and ▁r ena issance ▁of ▁the ▁Jose on ▁ ▁After ▁invas ions ▁from ▁Japan ▁and ▁Man ch uria , ▁Jose on ▁experienced ▁a ▁nearly ▁ 2 0 0 - year ▁period ▁of ▁peace . ▁Jose on ▁witness ed ▁the ▁emer gence ▁of ▁Sil h ak ▁( P ract ical ▁Learning ). ▁The ▁early ▁group ▁of ▁Sil h ak ▁sch ol ars ▁advoc ated ▁compreh ensive ▁reform ▁of ▁civil ▁service ▁exam ination , ▁tax ation , ▁natural ▁sciences ▁and ▁the ▁improvement ▁in ▁ag rom an ager ial ▁and ▁agricult ural ▁techniques . ▁It ▁aim ed ▁to ▁re build ▁Jose on ▁society ▁after ▁it ▁had ▁been ▁dev ast ated ▁by ▁the ▁two ▁invas ions . ▁Under ▁the ▁leadership ▁of ▁Kim ▁Y uk , ▁the ▁chief ▁minister ▁of ▁King ▁H ye on j ong , ▁the ▁implementation ▁of ▁re forms ▁proved ▁highly ▁advantage ous ▁both ▁to ▁state ▁reven ues ▁and ▁to ▁the ▁lot ▁of ▁the ▁pe as ants . ▁ ▁F action al ▁conflict ▁grew ▁particularly ▁inten se ▁under ▁the ▁reign s ▁of ▁the ▁k ings ▁Su k j ong ▁and ▁G ye ong j ong , ▁with ▁major ▁rapid ▁revers als ▁of ▁the ▁r uling ▁fa ction , ▁known ▁as ▁* hw angu k * ▁( <0xE6> <0x8F> <0x9B> 局 ; ▁literally ▁change ▁in ▁the ▁state ▁of ▁affairs ), ▁being ▁common place . ▁As ▁a