Gutoku-sho (literally, idiot monks note) (愚禿鈔)
"Gutoku-sho" is a treatise written by Shinran on his own religious faith through his master's teaching of the Jodo (Pure Land) sect. Consisting of two volumes notes, "Jo (vol. 1)," and "Ge (vol. 2)," it is also referred to as "Nikan-sho" (literally, two volumes of notes). The treatise explains one of the doctrinal bases of the Jodo Shinshu (the True Pure Land Sect of Buddhism).
Since the colophon of the manuscript which Senju-ji Temple reserves reads that this was written on August 27, 1255, it is believed that Shinran wrote "Gutoku-sho" around that time.
The "Gutoku-sho" doesn't exist in Shinran's own handwriting. The oldest extant manuscript is the transcription of Kenchi, collection of Senju-ji Temple of the Takada school of the Jodo Shinshu (copied on November 12, 1293).
This manuscript is composed of three volumes, 'Jo (vol. 1),' 'Hon (vol. 2),' and 'Matsu (vol. 3).'
('Hon' and 'Matsu' correspond to 'Ge.')
Another extant manuscript is the transcription of Zonkaku, collection of Joraku-ji Temple (Shimogyo Ward) (Kyoto City) of the Hongan-ji Temple school of Jodo Shinshu (vol. 1 copied on October 19, 1342 and vol. 2 on January 21, 1341).