Caturmudra (four kinds of seal) is the yoga fulfillment method in Tattvasamgraha, which is the basic structure of the scriptures. In this article, we considered how Caturmudra is explained in Rishukyo-series (Prajnaparamita-sutra). In Rishukyo (Adhyardhasa-prajnaparamita), “kaya-vak-citta-vajra 身語心金剛,” which is a replacement for Caturmudra, is explained in the sixth column as four types of seals.
Regarding the fourth of the four types, the one that was “Kongo-chi-in 金剛智印” in the Genjo 玄奘 translation (Bodairushi 菩提流志 translation and Kongochi 金剛智 translation) was changed to “Kongo-in 金剛印” after the non-empty translation. In addition, differences in the contents of “Kongo-in” became clear in the series after the translation of Fuku 不空. Based on these, at the end of this article, we considered the relationship between the Rishukyo-series and Tattvasamgraha.