法華玄義釋籤 4.50

4.50

第七意者，四各有絕，故名為「橫」，今三從圓迭至觀心，故名為「豎」。

Seventh, regarding the intention: the four [teachings] each have transcendence, and are thus called “horizontal”; the present three proceed from the perfect in turn down to the contemplation of the mind, and are thus called “vertical”.