"Suffice it to say that there are many approaches to meditation in Buddhadharma that are to be found under the headings of Ch'an and Ch'an Ting. Ch'an Ting alone is an umbrella name for many methods: the Four Dhyanas, the Four Infinities, the Four-Void Worldly Ch'an, the Nine Observations, the Samadhi of Nine Degrees (supramundane), the Ch'an of Self-Nature and the Ch'an Ting. These approaches can lead one to deep dhyana, where real wisdom is to be found; and with real wisdom, there can be self-enlightenment, enlightenment of others and the Ultimate Perfect Enlightenment."
(The Fundamentals of Meditation Practice by Ting Chen, tr. Lok To, p. 71,
PDF)
In the above book Ting Chen (about whom I have no information) gives meditation guidance mostly according to Zhiyi's manual of Six Gates and in general the samatha-vipasyana method.
"The Sweet Dews of Chan" (
PDF) by Cheng Kuan, who is a 20th century Chinese monk, gives a rather traditional instruction that includes the dhyanas and even meditation on a corpse.
But, as I've mentioned before, it is not easy to pinpoint what Chan stands for. Since it can include any method, there are no restrictions. On the other hand, what is called the Chan School has always embraced the direct path.
Huangbo said,
"From now on whenever walking, standing, sitting or lying down, only practise no-mind. You wait for a long time to have true realisation, because you have little strength for sudden break through. So for three, five, or even ten years you wait to obtain entrance and naturally progress then on. Because you are not that sort of person, you have the need to practise meditation and practise the path. But what does that have to do with the Buddhadharma?" (T48n2012Ap0383c05-08, my translation)
Zongmi's "sudden enlightenment, gradual practice" approach is not really different. Zongmi says, "Therefore, from the first time one produces the thought [of awakening] up to and including becoming a buddha [it is] just calm, just Knowing, immutable and uninterrupted. It is just that according to the stage [of practice] the terminology differs somewhat." (Zongmi on Chan, p. 94)
What is that gradual practice then? Jinul says,
"From this passage we see that the "no-mind which conforms with the path" of the patriarchs' school is not bound by samadhi and prajna. And why is this? The training in samlidhi accords with the noumenon and absorbs all scatteredness; hence it involves the power which can forget conditioning [by lessening the entrancement with sense-objects]. The training in prajna investigates dharmas and contemplates their voidness; hence it involves the effort of effacement [by clearing away the deluded process of thought]. In the direct cognition of no-mind which frees your path of obstructions, the unhindered wisdom of liberation manifests before you and not even one sense-object or thought can enter from outside. They are nothing special; why waste your effort on them?"
(Collected Works of Chinul, p. 286-287)
Zongmi, also quoted by Jinul, explains here the meaning of gradual cultivation within Chan, as different from common gradual techniques. This matches the idea of continuing the original practice of no-thought, what in Dogen's case is called shikantaza.
"If one's practice is based on having all-at-once awakened to the realization that one's own mind is from the outset pure, that the depravities have never existed, that the nature of the wisdom without outflows is from the outset complete, that this mind is buddha, that they are ultimately without difference, then it is dhyana of the highest vehicle. This type is also known by such names as tathagata-purity dhyana, the one-practice concentration, and the thusness concentration. It is the basis of all concentrations. If one can practice it from moment to moment, one will naturally and gradually attain the myriad concentrations. This is precisely the dhyana that has been transmitted down from Bodhidharma. Before Bodhidharma arrived, all of the scholars from early times had understood only the four dhyanas [of the realm of form] and the eight concentrations [that is, those four plus the four formless concentrations of the formless realm]. Various illustrious monks had effectively practiced them, and they had all obtained results. Nanyue [Huisi] and Tiantai [Zhiyi] relied upon the principle of the three truths to practice the three tranquilizations and three viewings. Although the principles of their teachings are most perfect, their entrance gate is step-by-step. It also involves the type of dhyana mentioned above. It is only in the transmission from Bodhidharma that the practitioner all-at-once identifies with buddha substance. This is like no other gate."
(Zongmi on Chan, p. 103-104)
Hanshan Deqing advises the same,
"So called sudden enlightenment and gradual practice refers to one who has experienced a thorough enlightenment but, still has remnant habit tendencies that are not instantaneously purified. For these people, they must, implement the principles from their enlightenment that they have realized to face all circumstances of life and, bring forth the strength from their contemplation and illumination to experience their minds in difficult situations. When one portion of their experience in such situations accords[with the enlightened way], they will have actualized one portion of the Dharmakaya. When they dissolve away one portion of their deluded thinking, that is the degree to which their fundamental wisdom manifests. What is critical is seamless continuity in the practice. [For these people,] it is much more effective when they practice in different real life situations."
(
Essentials of Practice and Enlightenment for Beginners)
But there is another point that should be considered, whether one faces stronger or weaker defilements. In this case application of general methods is recommended.
"Question: Having awakened to the true mind of the third teaching, how does one practice it? Does one employ the cross-legged Chan sitting of the first teaching?
Answer: The person who is prone to turbulent, uncontrollable emotions does make use of the teaching devices of the first teaching, but the person of weak depravities and strong intellect relies on the one-practice concentration (samadhi) of Southern Chan and the third teaching. The one-practice concentration is movement and is carried out in the midst of all activities."
(Zongmi on Chan, p. 139)
Finally, Zongmi actually gives an explanation for the case when teachers have to use first the gradual methods to bring students to sudden enlightenment. And this is where the use of dhyanas fits very well.
"In a master-student transmission, [the master] must know the medicine [for each and every] disease. This means that all instructional teaching devices inherited from the past first show the original nature and then require reliance on this nature to practice dhyana. In most cases, when the nature is not easily awakened to, it is due to the grasping of characteristics. Thus, if [a master] wants to reveal this nature, he must first eradicate grasping [on the part of the student]. In [the master's] teaching devices for eradicating this grasping, he must [employ a type of rhetoric in which] common person and noble one are both cut off, merits and faults are both gotten rid of, in the precepts there is neither violation nor observance, in dhyana there is neither concentration nor distraction, the thirty-two marks are all like flowers in the sky, and the thirtyseven parts of the path58 are all a dream or illusion. The idea is that, if [the master] enables [the student] to have a mind free of attachment, then [the student] can practice dhyana."
(Zongmi on Chan, p. 119)