金光明最勝王經疏 2.36

2.36

Sūtra: Upon the lotus flowers were four Tathāgatas: Akṣobhya in the east, Ratnaketu in the south, Amitāyus in the west, and Dundubhisvararāja in the north. These four Tathāgatas were each seated cross-legged on their thrones.