"A Chan practitioner should not by way of dhyāna cultivation bring the conscious mind (manovijnana) to a state where it is “non-knowing of the six sense-objects.” Such a mental state exists only in the samāpatti (deep mental absorption) in the Second Dhyāna or above, wherein the consciousness no longer discerns the five sense-objects. Since this kind of mental state is still within the bounds of the consciousness, it is not the Prajna Wisdom of True Reality that a practitioner should seek to realize via the tenet/principle of Chan. On the contrary, a Chan practitioner should first acquire the skill of meditative concentration, specifically, the ability to guard a “huatou 話頭” (word-head). However, once his consciousness has acquired concentration skill, instead of entering it into a samādhi state, the practitioner should allow it to immerse in and experience all six sense-objects in daily life. This is the correct way to locate the True Mind, the Mind that is truly “non-knowing of the six sense-objects” yet exists in concurrence with the consciousness. In short, the conscious mind is aware of the six sense-objects, but a Chan practitioner ought not regard the conscious mind’s detachment from the five sense-objects as the awakening to the True Mind."
The Dharma Eye of Chan School, p.360