Lit. Sanskrit motif. A Sanskrit character, bonji 梵字, that decorates pendants *gatō 瓦当; semi-cylindrical, convex eave-end tiles *nokimarugawara 軒丸瓦; or broad concave eave end tiles *nokihiragawara 軒平瓦. The character first appeared in the 11th-12th century. The bonjimon fills the entire surface of the pendant attached to the nokimarugawara. A late Heian period pendant unearthed at the Rokkakudō 六角堂 of Chōhōji 長法寺 in Kyoto has a diameter of 10 cm. A damaged pendant that was once attached to a nokimarugawara excavated at Shitennōji 四天王寺 in Osaka dates between the end of the 11th and late 12th century and has a diameter of 14 cm. The rim was probably plain. The Sanskrit character is in the center but instead of filling the entire field, it is enclosed by a fluted border composed of stylized stamen which in turn is surrounded by an eight-double-petaled lotus motif called *fukuben rengemon 複弁蓮華文. This is said to be a unique treatment. The use of Sanskrit characters on eave end tiles *nokigawara 軒瓦, relates to the introduction of the Esoteric Buddhist sects of Shingon 真言 and Tendai 天台, which were brought to Japan from China by *Kūkai 空海 (774-835) and Saichō 最澄 (767-822).
