He spent only six months in China on this first trip, but returned in 1187 for a longer stay as a disciple of Xuan Huaichang, a master in the Linji (Rinzai) line, at Jingde Si (Ching-te-ssu, 景德寺) monastery.

The prayer rituals and recitation of sutras that Eisai integrated into his monastic routines can be traced back to the Rules of Purity established during the Chinese Song dynasty.

[4] Eisai set about slowly propagating the new faith, trying to gain the respect of both the Tendai school and the Imperial court through careful diplomacy.

Faced with the sometimes violent opposition of traditional schools of Buddhism such as Tendai, Shingon and Pure Land, Eisai finally left Kyoto for the north-east to Kamakura in 1199, where the shōgun and the newly ascendant warrior class enthusiastically welcomed his teachings.

Though he is credited with transmission of the Rinzai line to Japan, it remained for later teachers to establish a distinctly Japanese Zen free of admixture with the teachings of other schools.

Eisai lived through an era of heavy fighting in Japan, so mappō played a big role in his promotion of tea, as he thought it was a cure for many ailments and hence would help people get through this perceived difficult time.

In Kissa Yōjōki, the beginning bulk of text after the prefaces concern the alignment of the five elements of Chinese science (earth, fire, water, wood, and metal) with five major organs (the liver, lungs, heart, spleen, and kidneys) and the respective five flavors that each major organ preferred (acidic, pungent, bitter, sweet, and salty).