A reference to the establishment of the doctrine of one vehicle (fourth vehicle) by Guangzhai based on his interpretation of the parable of the burning house in the Lotus Sutra 法華經. This is an important special characteristic of the Tiantai and Huayan schools.

光宅，即南朝梁光宅寺之法雲法師。師依法華經譬喻品所說之四車，判釋佛陀一代之教說為四乘教，故稱光宅四乘。據華嚴五教章卷一、華嚴經探玄記卷一等載，即：(一)以羊車比喻聲聞乘，(二)以鹿車比喻緣覺乘，(三)以牛車比喻菩薩乘，(四)以大白牛車比喻佛果一乘。此乃光宅於三乘教之外，別立圓融之一乘教；以三乘教為說法華以前之權教，一乘教為法華一乘之實教，開啟天台、華嚴諸宗之基礎。〔法華義經記卷四、法華經玄義卷十上、五教章通路記卷十三〕（參閱「火宅喻」1495、「四教」1759）

===（名數）光宅法師依法華經譬喻品之意立四乘教：一羊車謂聲聞乘，二鹿車謂緣覺乘，三牛車謂小乘之菩薩，四大白牛車謂大乘之菩薩。是於三乘教外，別發明純大之一乘教，開天台華嚴諸大乘之基礎者。見華嚴大疏一，三藏法數十五。