Thirteen Buddhas. A set of thirteen Buddhist deities, including *myōō 明王 (Sk: vidyaraja) and *bosatsu 菩薩 (Sk: bodhisattva). They are invoked at the thirteen memorial services traditionally held for the dead. A purely Japanese convention that had evolved by the 14th century and was popularized during the following century, the Thirteen Buddhas are thought to have developed from the belief in ten kings of the underworld *jūō 十王 who were regarded as manifestations of ten Buddhas jūbutsu 十仏, to whom further three Buddhas were added. In addition to sets of statuary representations of the Thirteen Buddhas, there exist large numbers of stone tablets *itabi 板碑 either portraying the Buddhas themselves or inscribed with their seed-syllables shuji 種子. They are similarly represented in hanging scrolls that are still used today at memorial services for the dead. The names of the Thirteen Buddhas and the corresponding memorial services are as follows: *Fudō Myōō 不動明王 (7th day), *Shaka 釈迦 (27th day), *Monju 文殊 (37th day), *Fugen 普賢 (47th day), *Jizō 地蔵 (57th day), *Miroku 弥勒 (67th day), *Yakushi 薬師 (77th day), *Kannon 観音 (100th day), *Seishi 勢至 (1st anniversary), *Amida 阿弥陀 (3rd anniversary), *Ashuku 阿しゅく (7th anniversary), *Dainichi 大日 (13th anniversary), and *Kokūzō 虚空蔵 (33rd anniversary).