Caoshan Benji (曹山本寂, गिरिशान्ति - Giriśānti; ཚའོ་ཧྲན་པེན་ཅི། tsha'o hran pen ci Tsaoshan Benji], universally revered across [[China, Japan, Korea, Vietnam, and East Asia as Yuanzheng Chanshi - 元證禪師, Chan Master of Primordial Verification, and in Japan as Sōzan Honjaku), acclaimed throughout East Asian Buddhist history as the foremost 9th century Dharma heir of Dongshan Liangjie (807–869) and the co-founder—whose Dharma name lent the first character to the Caodong (Sōtō) school of Chan Buddhism—stands as one of the sharpest dialecticians and contemplative masters in the Chinese Tripitaka. With his year of birth in 840 and his year of death in 901, Caoshan Benji was born into the scholarly Huang family in Putian in Fujian province, China. Gifted with prodigious literary brilliance and philosophical acuity from early childhood, he mastered the Confucian classics before recognizing the pervasive reality of anicca and dukkha, practicing fearless renunciation at age nineteen, taking formal refuge in the Buddha, the Dharma, and the Sangha, entering the monastic order at Lingshi Monastery in Fuzhou, and receiving full monastic ordination at age twenty-five in the Dharmaguptaka Vinaya Pitaka lineage while upholding strict monastic precepts and ethical conduct.
Determined to penetrate the supreme matter of birth and death directly rather than settle for purely academic scholarship, Caoshan Benji journeyed northward to Mount Dong (Dongshan) in Jiangxi province to study directly under Dongshan Liangjie, engaging in austere single-pointed meditation, mindfulness, and concentration under his master's intimate mentorship. During a famous encounter dialogue when Dongshan Liangjie asked him what his name was, Caoshan Benji replied “Benji” (Primordial Stillness), and when Dongshan Liangjie pressed him further to speak beyond that, Caoshan Benji answered that he would not speak further because then it would no longer be called Benji, prompting Dongshan Liangjie to recognize his profound realization of non-duality and transmit to him the esoteric seal of the lineage alongside the Baojing Sanmei Ge (Song of the Precious Mirror Samadhi).
Following Dongshan Liangjie's parinirvana in 869, Caoshan Benji traveled to Fuzhou in Jiangxi province and settled on Mount Cao (Caoshan, named after the Sixth Patriarch Huineng's mountain seat at Caoxi), where he established a vibrant contemplative community, later teaching also on Mount Heyu at the invitation of local officials and attracting hundreds of dedicated monastics and lay seekers from across southern China.
Literarily, Caoshan Benji left a brilliant philosophical and poetic legacy preserved in the Chinese Tripitaka in the Fuzhou Caoshan Benji Chanshi Yulu (撫州曹山本寂禪師語錄, Recorded Sayings of Chan Master Caoshan Benji, Taisho Number 1987B in the Chinese Tripitaka), the Jingde Chuandeng Lu (景德傳燈錄, Taisho Number 2076), and his authoritative prose commentaries on Dongshan Liangjie's Wuwei Xianjue (Five Ranks of Apparent and Real) and the Baojing Sanmei Ge, which codified the theoretical vocabulary of the Caodong tradition for centuries.
Philosophically and contemplatively, Caoshan Benji refined and systematized Dongshan Liangjie's Five Ranks (Wuwei, 五位) alongside his own celebrated formulation of the Four Ways of Knowing and Dropping (Sichong Lijian), illustrating the dynamic interplay between absolute principle (zheng, 正, corresponding to ultimate emptiness - शून्यता - śūnyatā; སྟོང་པ་ཉིད། stong pa nyid Tongpanyid) and relative phenomenal appearances (pian, 偏, corresponding to dependent origination and dependent co-arising). Using luminous metaphors such as the Lord and Vassal (Junchen Wuwei), Caoshan Benji demonstrated that ultimate reality and everyday phenomena are neither identical nor separate, but mutually interpenetrate without leaving a trace of conceptual dualism.
Harmonizing this subtle dialectical precision with Nagarjuna's Madhyamaka dialectics, Asanga's Yogacara phenomenology, Chengguan and Fazang's Huayan metaphysics, and the innate Buddha-nature (tathagatagarbha) teachings of the Mahaparinirvana Sutra (Taisho Number 374 and Toh Number 119 in the Tibetan Tripitaka) and Maitreya's Uttaratantra Shastra (Toh Number 4024 and Taisho Number 1611), Caoshan Benji showed practitioners how attachment to the five aggregates, anatta, emptiness of self, karma, and rebirth across samsara and nirvana dissolves naturally into clear right view and non-attachment.
Throughout his teaching career on Mount Cao and Mount Heyu—famously replying to a monk who asked why he saw no trace of spiritual attainment that “If there were any trace, it would be a stain upon the bright mirror”—Caoshan Benji wielded gentle, penetrating skillful means while anchoring monastic conduct in Shakyamuni Buddha's foundational teachings on the Four Noble Truths, the Noble Eightfold Path, generosity, merit, loving-kindness, compassion, equanimity, and universal bodhicitta to uproot the three poisons of greed, hatred, and delusion across the six realms.
Passing into final parinirvana on Mount Heyu in Jiangxi in 901 at the age of sixty-one seated upright in the lotus posture after dictating a final farewell verse to his assembled disciples and bequeathing his monastic robe and scriptures to his heirs, Caoshan Benji was posthumously honored by the imperial court with the title Yuanzheng Chanshi (Chan Master of Primordial Verification) and enshrined in the Fuyuan stupa. Revered across China, Korea, and Japan (as Sōzan Honjaku) as the co-founder whose name graces the Caodong and Sōtō schools, Caoshan Benji stands forever alongside Bodhidharma, Huineng, Dongshan Liangjie, Dōgen Zenji, and Nagarjuna as a supreme guardian of the Middle Way.