I just read an article about five kinds of Zen. It is excellent. It lists Tsung-mi as the originator of the idea of five kinds of Zen practice.
I’ve found Tsung-mi’s writings to be very helpful in many ways but not on par with T’ien-t’ai or Miao-lo. [Miao-lo [妙楽] (711–782) PY Miaole; Japanese: Myōraku, also known as Chan-jan. The sixth patriarch of the T’ien-t’ai school in China, in the tradition that counts T’ien-t’ai as the first patriarch.]
The only problem I had with article was that I don’t think it’s explanation of Shojo or Hinayana Zen was very clear. It also is unfair to actual pre-Mahayana teaching. Let me explain, if one gets caught in it just trying to cut off craving and ignorance through bare non-judgmental awareness of phenomena and through that is able to attain insight into the impermanent, ultimately ungraspable and selfless nature of phenomena I would say that it is Hinayana practice, because it does not open one up beyond one’s own direct knowledge of being free of craving and seeing that selflessness. This is an important step to take - to get that direct non-judgmental craving free awareness but the next step is into the Daijojo or Mahayana practice.
The article however, (and this happens often in East Asian Buddhism, even T’ien-t’ai does it) conflates that with being complacently satisfied with the states of dhyana (or zen or meditative absorption) which is a temporary respite from craving. That should actually be relegated to the Gedo (outside-way) practice, as these states correlate to rebirth in the Heavens of Brahma.
Also, the article doesn’t touch on it but another possible distinction between the last two types of practice - the Mahayana and the Saijojo or Great and Perfect practice is that of these five types the Mahayana practice is the practice of striving to become a buddha, whereas the Great and Perfect practice is the practice of simply being buddha. It is the difference between the faith that one can attain buddhahood (in the future, as per the predictions of chapters 2-9 of the Lotus Sutra) and the faith that is one already a buddha (as per the non-arising and non-ceasing nature of buddhahood explained in chapter 16).
In other words, I would say there is the practice of the Trace Gate wherein one has faith one will realize buddhahood and the practice of the Origin Gate wherein one has faith that realization is making itself known as needed in your life here and now.
https://wwzc.org/dharma-text/begin-here-five-styles-zen