This paper represents an attempt at the textual criticism of several of Shinran's writings. As the result of this attempt I found that he rewrote some works in his last year, for example, changing certain terms from Tenjin 天親 to Seshin 世親 (Vasubandu) and from shujo 衆生 to ujo 有情 (sattva).
In addition he used new terms, toshogaku 等正覺 and mujogaku 無上覺, for the first time at the age of eighty-five. These rewritings are due to the fact that he was facing difficult problems such as strife with his son Zenran and opposition to the Nembutsu.
So he increased his focus on Mappo consciousness, and used new terms in his last year.
Ujo signifies that all beings strive to live always to the utmost. On this account Shinran thought ujo better than shujo.
In the history of Chinese translations of Buddhist scriptures, the term shujo is older than ujo. Shinran used the new term ujo consciously rather than the older shujo.