The twelve main channels are grouped into six layers or six levels of depth, also called unitary channels. Three of them form the Yang gate and the other three form the Yin gate. See Main Channels.

When the Yang gate opens, the Yin gate must close. These movements are relative. For example: when winter arrives, the Yang gate must close to open the Yin gate and begin conservation and regeneration in preparation for the new season. When spring arrives, the Yin gate must close and the Yang gate must open for growth and expansion.

• Spring: externalizes (yang).
• Winter: internalizes (yin).

External pathogenic energies (wind, cold, dampness, dryness, heat and fire) can penetrate into some of these six layers and block their movement. Each affected layer expresses certain symptoms, which allows us to identify which layer the blockage is in and choose the appropriate treatment to restore the movement of both gates.

Yang Gate

Its movement is one of growth, externalizing energy. Expansion.

• Tai Yang Layer: opening (kai) (ascending). Cold.
• Shao Yang Layer: hinge (shu) (ascending - descending). Heat.
• Yang Ming Layer: closing (he) (descending). Dryness.

Yin Gate

Its movement is one of conservation, internalization, and regeneration of energy. Reserve.

• Tai Yin Layer: opening (ascending). Dampness.
• Shao Yin Layer: hinge (ascending - descending). Fire.
• Jue Yin Layer: closing (descending). Wind.

The order mentioned above corresponds to the book Shang Han Lun, the Treatise on Cold-induced Diseases. A couple of quotes from the Su Wen, chapter 6, also support this view:

• The greater Yin functions as the external opening, the declining Yin functions as the internal opening, and the lesser Yin plays the role of axis.
• Therefore, in the separation and reunion of the 3 yīn, tài yīn is the opening [as it extends and irrigates]; jué yīn is the closing [as it transmits to the interior]; shào yīn is the axis [as it transports between the opening and the closing].

There is another current of Traditional Chinese Medicine schools that refers to a different order in the layers of the Yin gate. The fire school current (Kai He Shu) defends the following order:

• Tai Yin Layer: superficial.
• Jue Yin Layer: hinge.
• Shao Yin Layer: deep.

Qi and Blood

• The Tai Yang Layer contains more Blood than Qi and when blocked it produces great pain. Cold freezes the Blood and Blood stasis produces intense, stabbing pain.

• The Shao Yang Layer contains more Qi than Blood. It is the hinge. It allows energy to circulate both inward and outward.

• The Yang Ming Layer is abundant in both Blood and Qi, in equal proportions.

• The Tai Yin Layer moves more Qi than Blood. It opens the Yin gate.

• The Shao Yin Layer moves more Blood than Qi. It is the hinge of the Yin gate.

• The Jue Yin Layer moves more Qi than Blood. It closes the Yin gate.

The work we must do is to allow this movement.

When we needle, we sometimes inadvertently cause bleeding in patients. There are channels where there is a lot of Blood and nothing happens, whereas bleeding channels with little Blood is not good — the treatment may not work.

The concept of Blood referred to here does not correspond to that of the blood test done by a doctor. We are referring to Xue, the energetic aspect of Blood, its hydrating and nourishing quality (yin) as opposed to Qi, which is movement and warming (yang).

Examples

If a patient has Tai Yang blocked, their movement of externalization is blocked by cold. If so, I treat Tai Yang to unblock it. Any point from the Tai Yang channel can be chosen: BL or SI; it is better to use the five Antique Shu Points, points of movement.

• SI-3 + BL-62.

For this channel to defend against exterior cold, Tai Yang is connected to the Du Mai and draws on its energy; Du Mai mobilizes the Yang of all channels.

• Jing-River Point (BL-60), Fire element, to warm.
• Ashi points locally. When an acupuncture point coincides with an Ashi point, the treatment is more effective. Even if they do not coincide, I treat the Ashi point.

If this treatment does not resolve the problem, I can move on to treating Shao Yang so that Tai Yang has more strength to open. E.g.: I have back pain and the pain also moves toward the side of the body or the leg. I can use:

• Shao Yang points that have indications to treat regions of the body (e.g.: TE-3).
• If I cannot remember, I use: TE-5 + GB-41 (Yang Wei Mai) to open everything.

If it still does not work, I can use Jue Yin, to check whether it is not closed. If someone tells us: my pain worsens with the weather and stress, in this case Jue Yin is very important.

• LR-3 + PC-6 - releases emotional problems.

Another example: scapular periarthritis. Significant inflammation around the shoulder joint (frozen shoulder). I palpate and all the channels in the area are painful. This means the entire Yang gate is blocked (opening, hinge, closing). Where do I begin?

• Which gate opens toward this gate? Tai Yin (reaches all three Yang levels). I open the Yin gate to see if the Yang gate responds. I use LU-5 (one of the possible points).
• Tai Yin does not have sufficient strength and I support it with Shao Yin, the hinge: KI-2 (one of the possible points, a way of alternating foot and hand).
• Jue Yin only reaches Tai Yang, which is why I wait to work with it; it is better to work with Tai Yin. We do not want to close the Yin gate — we need it open.
• When the energy begins to move, I can then treat the three Yang levels: Shao Yang, Yang Ming, and Tai Yang.