Vatsiputriya (Wyl. gnas ma bu pa'i sde) - a branch of the Sammitiya school of the basic vehicle, whose followers asserted the existence of an 'inexpressible self' (brjod du med pa'i bdag), which can not be said to be either the same as, or distinct from, the five aggregates, or as either permanent or impermanent, and so on. This assertion was refuted by other schools, and by Dignaga, who was once a follower of this tradition under a teacher called Nagadatta. One on occasion, the young Dignaga sat meditating in his room, naked, and surrounded by lots of lamps. When the teacher came in and asked him what he was doing, he said: “Teacher, you told us there is an inexpressible self within our bodies, so I am looking for it!” Then the teacher realized he was being mocked, so he expelled the student, who, of couse, went on to become one of the most famous scholars in all of India.