A Commentary on the Mirror that Clarifies the Essence (Snying po gsal ba'i me long zhes bya ba'i khrid) is contained in the Seminal Heart in Four Parts (Snying thig ya bzhi) which is a collection compiled and partly composed by Longchen Rapjam Drimé Özer (1308-1364). This collection of profound Dzokchen teachings consists of the (1) The Seminal Heart of the Ḍakiṇī (Mkha’ ‘gro snying thig), (2) The Seminal Quintessence of the Ḍakiṇī (Mkha’ ‘gro yang tig) (3) The Seminal Heart of Vimalamitra (Bi ma snying thig), (4) The Seminal Quintessence of the Spiritual Teacher (Bla ma yang tig), and (5) The Profound Seminal Quintessence (Zab mo yang tig). This edition was reproduced from the original xylograph belonging to the late Kathog Ontrul.