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.
専修寺本の奥書には、「建長7年乙卯（1255年）8月27日書之」と記されていて、その頃に撰述したものと考えられる。