/r/zen Buddhism is divided into 3 schools Theravada – oldest surviving school Mahayana – largest school Vajrayana – often mistakenly called “Tibetan Buddhism”, the Dalai Lama is the spiritual leader of one of the sects of this school Zen Buddhism, the full name, is part of the Mahayana school. The moderators of /r/zen claim that “zen” is not part of Buddhism, and is not “Zen Buddhism”. I asked them about it a few years ago and they gave me quite the lengthy explanation in that regard despite the world saying otherwise. This situation has been the case for decades – only use Reddit as an invitation to do further research.