Katog Dorjeydan Monastery (Ka:-thog rDo-rje gdan dGon-pa, Kathog Monastery), located in the Derge (sDe-dge) district of the southeastern Tibetan province of Kham (Khams), is one of the six main Nyingma monasteries. It was founded in 1159 by Kadampa Desheg (Ka-dam-pa bDe-gshegs) (1122-1192).
Guru Rinpoche Padmasambahva (Gur-ru Rin-po-che Pad-ma ‘byung-gnas) had prophesied that to the east, in Kham, on the slopes of a rock mountain shaped like a lion, there would be a monastery called Ka that would be of irreversible benefit to the teachings and future disciples. Furthermore, Kadampa Desheg’s teacher, Jamton Rinpoche (‘Jam-ston Rin-po-che), had told him that if he went to Katog (literally, "on top of ka:"), it would be very beneficial for the practice of countless beings. Based on these prophesies, Kadampa Desheg searched for such a site and found it on the slopes of Yulri Mountain (Yul-ri). Not only did the mountain have a shape resembling that of a lion, but also on it he found a naturally formed letter "ka:" on a rock. He built the main temple of the monastery on top of the "ka:," and named it "Katog." In this way, all the prophesies were fulfilled.
Kadampa Desheg himself was prophesied by Padmasamhava, who said, "In the future I shall emanate in the form of a monk and establish Katog. I shall further the tantra, uphold all the teachings, and lead those with connection to the Pure Land Sukhavati (bDe-ba can)." Before he studied the Nyingma tradition with Jamton Rinpoche, Kadampa Desheg had mastered the Kagyu Mahamudra (phyag-chen, great seal) and Kadampa teachings under Gampopa (Dvags-po Lha-rje sGam-po-pa bSod-nams rin-chen) (1079-1153).
Katog has 112 branch monasteries, not only in Tibet, but also in Mongolia, Inner China, Yunnan, and Sikkim. For instance, Katog Rigdzin-tsewang-norbu (Ka:-thog Rigs-‘dzin Tshe-dbang nor-bu) (1698-1755) founded a large branch in Sikkim, and when the Eighth Tai Situ Rinpoche, Situ Panchen Chokyi-jungney (Si-tu Pan-chen Chos-kyi ‘byung-gnas) (1700-1774), visited China, he stayed at the Katog branch-monastery at the Five-Peaked Mountain of Manjushri (Ri-bo rtse-lnga, Chin: Wutai Shan), to the southwest of Beijing.
Rigdzin Tsewang Norbu is well known for having transmitted the "zhentong" (gzhan-stong, other voidness) view to Situ Panchen. This view, originally found among the Jonang lineage (Jo-nang) of the Sakyas, had been refuted and suppressed during the time of the Fifth Dalai Lama, Ngawang Lozang Gyatso (rGyal-dbang lnga-pa chen-po Ngag-dbang blo-bzang rgya-mtsho) (1617-1682). Situ Panchen, from the Karma Kagyu lineage, popularized the other-voidness view once more. It is found particularly among the many masters of the Karma Kagyu, Shangpa Kagyu, and Nyingma schools. Its form among them, however, is different from that purportedly ascribed to the Jonangpas, which masters from all four Tibetan traditions have rejected. Furthermore, the Kagyu and Nyingma interpretations differ from each other.
The traditional course of study and practice at Katog Monastery included sutra, tantra, medicine, astrology, grammar, and poetry. At its height in 1959, the monastery had 1050 monks.