ant ▁on ▁cultiv ated ▁plants ▁in ▁their ▁di ets . ▁The ▁subs istence ▁system ▁of ▁the ▁interior ▁settlement s ▁was ▁probably ▁not ▁unlike ▁that ▁of ▁the ▁in cip ient ▁Early ▁M um un ▁pot tery ▁period ▁( c . ▁ 1 5 0 0 - 1 2 5 0 ▁BC ), ▁when ▁small - scale ▁sh ifting ▁cultiv ation ▁(" slash - and - burn ") ▁was ▁pract iced ▁in ▁addition ▁to ▁a ▁variety ▁of ▁other ▁subs istence ▁strateg ies . ▁The ▁Late ▁Je ul mun ▁is ▁roughly ▁contempor aneous ▁with ▁Lower ▁X ia ji ad ian ▁culture ▁in ▁L ia oning , ▁China . ▁Arch ae olog ists ▁have ▁suggested ▁that ▁Bang ud ae ▁and ▁Che on je on - ri , ▁a ▁substantial ▁group ▁of ▁pet rog lyph ▁pan els ▁in ▁U ls an , ▁may ▁date ▁to ▁this ▁sub - period , ▁but ▁this ▁is ▁the ▁subject ▁of ▁some ▁debate . ▁ ▁Kim ▁J ang su k ▁suggests ▁that ▁the ▁h unter - g ather er - c ult iv ators ▁of ▁the ▁Late ▁Je ul mun ▁were ▁gradually ▁disp la ced ▁from ▁their ▁" resource ▁patch es " ▁by ▁a ▁new ▁group ▁with ▁superior ▁slash - and - burn ▁cultiv ation ▁technology ▁and ▁who ▁migr ated ▁south ▁with ▁M um un ▁or ▁und ec or ated ▁( H ange ul : ▁▁ 무 문 토 기 ; ▁Han ja : ▁ 無 文 土 器 ) ▁pot tery . ▁Kim ▁explains ▁that ▁the ▁pattern ▁of ▁land ▁use ▁pract iced