brgyud pa'i bka' srol drug

Six Lineage Traditions. The buddha's mind lineage, the vidyadhara's sign lineage, the oral lineage of great masters, the dakini's entrustment lineage, the empowered aspiration lineage, the yellow parchment lineage There are other alternative lists. See Tulku Thondrup's Hidden Teachings of Tibet, Wisdom Publications [RY]