仁王經疏 3.321

3.321

釋曰：第二、作地別觀。謂入無相觀，離於有無及常斷等。或依十二緣生觀，離斷常故，名中道觀也。

Explanation: Second, engaging in the distinct contemplation of the bhūmi. It means entering the signless contemplation, free from existence and nonexistence, permanence and annihilation, and so forth. Alternatively, relying on the contemplation of twelvefold conditioned origination, being free from annihilation and permanence, it is called the contemplation of the middle way.