Further, Rennyo Shonin was the author of several works relating to Jōdo Shinshū doctrine. His most influential work is his collection of letters to various Shinshu "monto" (lay groups), popularly known as in the Nishi Hongan-ji tradition, and in the Higashi Hongan-ji tradition. These letters have the status of scriptural texts and are traditionally used in Shinshu daily liturgy; the most well-known letter is the which is a reflection on the impermanence of life and the importance of relying on Amida Buddha's Vow. This letter is frequently read aloud during Jōdo Shinshū funeral services.