This is called 'the sacred mountain of Ichijo Bodai Seito' (the mountain of the doctrine that only one Bodhi has a legitimacy to lead to enlightenment), and the name of the Tozan school (or Tozanho) is derived from it.
これを「一乗菩提正当（いちじょうぼだいしょうとう）の山」といい、このことから当山派（当山方とも）といわれるようになった。