Eisai Buddhist Japan: the "Lotus Sutra", "Golden Light Sutra", and the "Humane King Sutra" ("Ninnōkyō"). Eisai’s famous written piece, the "Kōzen gokokuron" or "The Promotion of Zen for the Protection of the Country", was heavily influenced by the "Ninno kyo" which states “the preservation of Buddhism is inextricably bound to the preservation of their own country”. The "Kōzen gokokuron" was written with the intention to correct established schools of Buddhism by giving them examples of moral practice and to convince the Minamoto military rulers to support Zen Buddhism and a Zen government. The writing promotes the Zen ideals to bring Buddhism
Zen expected to become familiar with the classics of the Zen canon". A review of the early historical documents and literature of early Zen masters clearly reveals that they were well versed in numerous Mahāyāna Buddhist sūtras, including Madhyamaka. Especially the Lotus Sutra played a large role in the development of East Asian Buddhism, including Zen. Nevertheless, Zen is often pictured as anti-intellectual. This picture of Zen emerged during the Song Dynasty (960–1297), when Chán became the dominant form of Buddhism in China, and gained great popularity among the educated and literary classes of Chinese society. The use of koans, which