In Fujiwara no Michinaga’s 藤原道長 Midō kanpaku-ki 御堂関白記 and Fuijwara no Sanesuke’s Shōyū- ki 小右記, diaries written in the second half of the tenth to the first half of the eleventh century, shuzen 修善 refers to esoteric Buddhist rituals （shuhō 修法） for worldly benefits.
In Minamoto no Toshifusa’s 源俊房 Suisa-ki 水左記 and Fujiwara no Moromichi’s 藤原師通 Gonijō Moromichi-ki 後二条師通記, both of which are from the second half of the eleventh century, there are fewer instances of this word. These texts use shuhō or rituals’ individual names to refer to Buddhist rituals carried out with the same aim as shuzen. This was because shuzen ceased to vaguely refer to esoteric Buddhist rituals during the latter half of the eleventh century, as a result of two factors. First, esoteric Buddhist rituals became common among Heian period aristocrats. Second, due to the spread of views regarding Pure Land rebirth, people became conscious of zengyō 善業― “good acts”―for rebirth in the Pure Land, affecting the semantic content of zen, the character shared by shuzen and zengyō.
