ing ▁China ▁interven ed ▁on ▁the ▁side ▁of ▁the ▁Kore ans , ▁sending ▁a ▁large ▁force ▁in ▁ 1 5 9 3 ▁which ▁pushed ▁back ▁the ▁Japanese ▁together ▁with ▁the ▁Kore ans . ▁ ▁During ▁the ▁war , ▁Kore ans ▁developed ▁powerful ▁fire ar ms ▁and ▁the ▁t urt le ▁ships . ▁The ▁Jose on ▁and ▁M ing ▁forces ▁defeated ▁the ▁Japanese ▁at ▁a ▁deep ▁price . ▁Following ▁the ▁war , ▁relations ▁between ▁Korea ▁and ▁Japan ▁were ▁completely ▁susp ended ▁until ▁ 1 6 0 9 . ▁ ▁Man ch u ▁invas ions ▁ ▁After ▁the ▁Japanese ▁invas ions , ▁the ▁Korean ▁Pen ins ula ▁was ▁dev ast ated . ▁Meanwhile , ▁Nur ha ci ▁( r . ▁ 1 5 8 3 – 1 6 2 6 ), ▁the ▁ch ie ft ain ▁of ▁the ▁J ian z hou ▁J urch ens , ▁was ▁un ifying ▁the ▁J urch en ▁tribes ▁of ▁Man ch uria ▁into ▁a ▁strong ▁coal ition ▁that ▁his ▁son ▁Hong ▁Ta iji ▁( r . ▁ 1 6 2 6 - – 1 6 4 3 ) ▁would ▁eventually ▁rename ▁the ▁" Man chus ." ▁After ▁he ▁declared ▁Seven ▁Gr iev ances ▁against ▁M ing ▁China ▁in ▁ 1 6 1 8 , ▁Nur ha ci ▁and ▁the ▁M ing ▁engaged ▁in ▁several ▁military ▁conflicts . ▁On ▁such ▁occasions , ▁Nur ha ci ▁required ▁help ▁from ▁G w ang ha eg un ▁of ▁Jose on ▁( r . 1 6 0 8 – 1 6 2 3 ),