Which Chinese Buddhist schools were gradualist?

There is a famous multicentury argument in the history of Chinese Buddhism as to if enlightenment is something achieved after gradual practice and improvement or something you realize or achieve in a flash of inspiration. Which schools were gradualists? Was this an actual distinction or was this a rhetorical device? Are there any surviving (as in existing right now) gradualist schools? Was Tien Tai/Tendai/Nichiren Buddhism gradualist?