As is well known, the Śūraṁgama-sūtra 大仏頂首楞厳経, an apocryphal sūtra believed to have originated in Tang China, was considered very important by various Buddhist sects during the Song dynasty, and Tiantai was no exception. Tiantai Shanwai 山外 lineage scholars, represented by Hushan Zhiyuan 孤山智円 （976-1064）, assigned the Śūraṁgama-sūtra to the Fifth Period （fahua niepan shi 法華涅槃時）, the highest rank in the Tiantai doctrinal classification known as the Five Periods （wushi 五時）. Likewise, some scholars of the rival Tiantai Shanjia 山家 lineage placed the sūtra in the Fifth Period. However, the opinions of Shanjia lineage scholars were not unified on this point.
The present paper focuses on Wo’an Benwu’s 我庵本無 （1285-1342） Dafoding shoulengyan jing shiti 大仏頂首楞厳経釈題, according to which the Śūraṁgama-sūtra belongs to the Third Period （fangdeng shi 方等時）. The paper demonstrates that although previous studies overlooked Benwu’s interpretation, there can be no doubt that Benwu clearly placed the Śūraṁgama-sūtra in the Third Period. It further shows that such an interpretation appeared in the Shanjia lineage during the Southern Song and Yuan dynasties.
