宋人詩文出現「六根互用」現象並非基於「通感」，而是依據《楞嚴經》如來藏真如心思想，真如心以六根為媒介來認識外境，故六根可互用；黃庭堅創作的「鼻觀詩」，則依據《楞嚴經》的圓通思想。《楞嚴經》認為萬法皆真心所現，真如心透過六根表現為根性，透過鼻根則為聞性。聞香「鼻觀詩」重在反聞自性，不僅能聞的聞性本自真如心，而且所聞的香氣也是真如心的性香。不論有無香氣，鼻根通塞，聞性一直起作用，常住不滅。後世文人所創作的各種「鼻觀詩」，尤以薝葡和木樨最為有名。日本五山詩僧推贊黃庭堅「鼻觀詩」，也是對其背後佛性論的肯定。

The “interoperability of the six roots” 六根互用, or six sense-organs—also known as the “six roots being unrestrained”—is based on the thought of Tathagatagarbha in the Shurangama Sutra, rather than the “penetrating sense” 通感, or synaesthesia. The Shurangama Sutra distinguishes the true mind and the delusive mind, and the former understands the world by means of the six roots, thereby making them functionally exchangeable. After the mid- to late Northern Song dynasty, one can note the emergence of “bi guan” 鼻觀 (lit. observances of the nose) poetry, represented by Huang Tingjian’s 黃庭堅 (1045-1105) compositions, that are related to the true mind and “perfect penetration” 圓通 of Buddhist thought. Similar to the “interoperability of the six roots,” Tathagatagarbha serves as the theoretical foundation of Huang Tingjian’s “bi guan” poetry. The myriad dharmas, according to the Shurangama Sutra, are embodied by the true mind, and through the six roots, the true mind manifests as “root-nature” 根性 (i.e., one’s true nature), with it being presented as “smell-nature” 聞性 through the nose. The emphasis of “bi guan” poetry is on reflecting our own nature. Not only the sense-organ of smell but all outside fragrances are also from the true mind, and regardless of whether the nose is obstructed or not, “smell-nature” is constantly in effect. Huang observes the outside world by means of “root-nature,” and in turn, the subject-object relationship disappears. The impact of his “bi guan” poetry is also notable as later writers, under his influence, likewise used fragrances, especially those of flowers such as tulips and osmanthus, as aesthetic objects to compose “bi guan” poetry. Moreover, Huang’s works were even admired by Japanese Zen monks of the Five Mountains, who largely validated the underlying Buddha-nature within the poetry.