▁used ▁in ▁battle ▁during ▁the ▁United ▁States ▁expedition ▁to ▁Korea ▁( 1 8 7 1 ), ▁when ▁the ▁US ▁Navy ▁attacked ▁Gang h wa ▁Island ▁in ▁ 1 8 7 1 . ▁The ▁US ▁Army ▁captured ▁one ▁of ▁the ▁v ests ▁and ▁took ▁it ▁to ▁the ▁US , ▁where ▁it ▁was ▁stored ▁at ▁the ▁Smith son ian ▁Museum ▁until ▁ 2 0 0 7 . ▁The ▁vest ▁has ▁since ▁been ▁sent ▁back ▁to ▁Korea ▁and ▁is ▁currently ▁on ▁display ▁to ▁the ▁public . ▁ ▁Econom y ▁ ▁Com merce ▁ ▁During ▁the ▁G ory e o ▁D ynast y , ▁Korea ▁had ▁a ▁health y ▁trade ▁relationship ▁with ▁the ▁Japanese , ▁Chinese , ▁and ▁Man ch uri ans . ▁An ▁example ▁of ▁prosper ous , ▁international ▁trade ▁port ▁is ▁Py ong nam . ▁Kore ans ▁offered ▁bro c ades , ▁j ew el ries , ▁g ins eng , ▁sil k , ▁and ▁por cel ain , ▁ren owned ▁famous ▁world wide . ▁But , ▁during ▁the ▁Jose on ▁D ynast y , ▁Conf u cian ism ▁was ▁adopted ▁as ▁the ▁national ▁philosophy , ▁and , ▁in ▁process ▁of ▁elimin ating ▁certain ▁Buddh ist ▁belief s , ▁G ory e o ▁Che ong ja ▁por cel ains ▁were ▁replaced ▁by ▁white ▁Ba ek ja , ▁which ▁lost ▁favour ▁of ▁the ▁Chinese . ▁Also , ▁commerce ▁became ▁more ▁restricted ▁during ▁this ▁time ▁in ▁order ▁to ▁promote ▁agricult ure . ▁Because ▁silver ▁was ▁used ▁as ▁currency ▁in ▁China , ▁it ▁played ▁an ▁important ▁role ▁in