In this particular context, "exoteric" means those teachings developed within the framework of Tendai Lotus Sutra studies, while "esoteric" refers to those based on the Ta-jih ching, Chin-kang-ting ching, and other sutras describing esoteric ritual practices. In reality, however, even the "exoteric" teachings of medieval Tendai contain esoteric elements.
The lineage of the Sanmai school which Honen received from Koen is, in chronological order: Kokei, Angei, Choen, Ryoyu, Chujin, Een, Joen, Koen and Honen. Within this tradition of the Sanmai line, there were three particularly important scholars: Kokei, Choen and Ryoyu. Kokei (977-1049) had founded a school of esotericism called the Tani school, from which most schools of Tendai esoteric teachings subsequently derived. Forty-three works are attributed to him. Choen (1016-1081) was Kokei's disciple, and his name appears in the esoteric lineages of Homan and Renge, as well as that of Sanmai. Thirty-two works are attributed to him, among which are the Ohara kuketsu, the Taizokai daikanjo hyoshiki, the Shijoketsu, and others. Ryoyu was the founder of the Sanmai school. His initial studies were conducted under Kokei, and later under Angei and Choen. Twenty-one works are attributed to him.
The lineage of the Renge school is as follows: Kokei, Choen, Eii, Ryonin, Eiku and Honen. Within this lineage, four works on esotericism are attributed to Eii. They are the Jinen jodoshiki, the Naisago kanchoshiki, the Himitsu kancho, and the Naisago kancho kuketsu. One of Honen's biographies, the Shui kotoku den-e, records that Eiku was famous for his teachings on esoteric Tendai Buddhism and on the Mahayana precepts. (HDZ 594.) The esoteric teachings here referred to may well refer to those of the Renge school.
Honen received from Koen the Sugiu line, later called the Yokawa Eshin school. This line came out of the Eshin school begun by Genshin, who transmitted its teachings to his disciple Kakucho (960-1034). It then passed in succession to Shohan (996-1077), Chogo, Chujin (1065-1138) and Kokaku. Within the Sugiu line, the two most important monks from the standpoint of medieval Tendai history were Chujin and Kokaku. Chujin is said to have been the first to write down and compile the orally transmitted teachings of the medieval Tendai Eshin school. While many of the twenty-three works (among them are the Hokkemongu yogi kikigaki, the Kankoruiju etc.) attributed to him are probably apocryphal, it is possible that some were in existence by Honen's time, and that he read them.
Honen received from Eiku the teachings of the Ohara school, a minor line of the Eshin school. The lineage of which is as follows: Kakucho (952-1034, the founder of the Kawa school. His writings are mainly concerned with Tendai esoteric teachings), Josei, Yuimyo, Enzen, Gensan, Ryoga, Ryonin, Eiku, and as Eiku's disciple Honen. Among these, the most famous are Ryoga and Ryonin. Ryoga was Ryonin's master and is also called Jijo bo Ajari. Three works are attributed to him: the Enai hoju shu (Commentary on the Fa-hua wen-chu), the Shisoi shiji, and the Chushakusho, including a commentary on Chih-i's Fa-hua wen-chu and a treatise on Indian logic (Skt. hetuvidya, Jp. inmyo).