From 役(やく) (yaku, “role”) + 作(つく)り (tsukuri, “making, 連(れん)用(よう)形(けい) (ren'yōkei, “stem or continuative form”) of the verb 作(つく)る (tsukuru).”).
やくづくり • (yakuzukuri) ←やくづくり (yakudukuri)?