 Little is known about the preparations for the 6th Congress . It was convened a decade after the 5th WPK Congress ( in 1970 ) , outside the party norm of a quadrennial meeting . There was no official reason for its postponement , but it was probably due to the fact that WPK General Secretary Kim Il @-@ sung spent much of the 1970s gathering support ( and creating an independent power base ) for his son and planned successor Kim Jong @-@ il . In addition , a great deal of time was spent restructuring party organizations and functions . The primary reason for the 6th Congress was to formalize Kim Jong @-@ il as Kim Il @-@ sung 's chosen successor . 
