The Parable of the Three Carts in the Lotus Sūtra, also known as the Parable of the Burning House, has been interpreted differently in Chinese Buddhist exegesis, with a division between the Three-Vehicle School (sanche jia 三車家 ) and the Four-Vehicle School (siche jia 四車家 ). The distinction lies in whether the ox-cart among the three carts is identical to the final great white ox-cart, which essentially reflects different understandings of the relationship between the Three Vehicles (triyāna) and the One Vehicle (ekayāna). This division already existed before the emergence of sectarian Buddhism. Early proponents of the Three-Vehicle interpretation include Huiguan, Sengzhao, Sengrui, Daosheng, and Liu Qiu; those of the Four-Vehicle interpretation include Fayun and Huisi. Fayun represents a crucial turning point, pioneering the Fourth Vehicle interpretation. Huisi, building upon this foundation, used his own contemplative experience and tathāgatagarbha theory to develop a second path for the Four-Vehicle School. The fundamental cause for the emergence of the Four-Vehicle School lies in the further polarization of the relationship between expedient means (upāya) and reality (tattva), which consequently granted the One Vehicle an independent status with concrete content.