What is "tannisho"

The , also known as the Lamentations of Divergences, is a late 13th century short Buddhist text generally thought to have been written by Yuien, a disciple of Shinran. In the Tannishō, Yuien is concerned about the rising doctrinal divergences that emerged in Jōdo Shinshū Buddhism after the death of their founder, so he wrote down dialogues between himself and Shinran that he could recall when his master was alive.

According to Yuien's own writing in the preface:

Many of the conversations found in the Tannishō are very candid when compared to more formal religious texts, and this may explain some of the popularity of the Tannishō among Shin Buddhists. The Tannishō allows Jōdo Shinshū Buddhists to peer into the mind of Shinran and see how he felt about practicing Jōdo Shinshū. The Tannishō was also a major impetus for the start of The Dobokai Movement among the Higashi Hongwanji branch of Jōdo Shinshū.