To address these questions accurately, we need to approach them one by one.
Let us begin with what the Upper, Middle and Lower Jiao represent, and how this compares to Chest Qi and the deeper function of San Jiao.

The concept of Three Jiaos originates in the Su Wen, which describes the San Jiao as “the official of drainage and sluices, from which the water-pathways arise.”
Although later texts divide the San Jiao into upper (above the diaphragm), middle (between diaphragm and navel), and lower (below the navel), it is essential to remember that these descriptions are functional, not anatomical.
The Jiaos are not fixed physical compartments, but rather a network of Qi transformations mediating between Heaven and Earth, Yin and Yang.

In clinical practice, we often interpret upper / middle / lower through different lenses — energetics, symptom patterns, or meridian pathways.

Viewed cosmologically, the Three Jiaos reflect the classical triad:

· Heaven – Upper Jiao: where we make contact with Heavenly Qi, allow life in, and reveal ourselves back.

· Earth – Middle Jiao: where post-natal Qi is formed, and lived experience becomes meaningful and “ours.”

· Man – Lower Jiao: where Jing is stored, where the root of Yuan Qi resides, and where we decide what continues and what must end.

Heaven creates Earth for the benefit of humanity, through the activity of the Three Jiaos, we live in accordance with the movement of Heaven and Earth.
The root of San Jiao lies in its hidden relationship with Yuan Qi 元.

When we speak about deep San Jiao, we refer to its function of distributing Yuan Qi — our collective ancestral energy, linking us to everything that came before us; a catalyst and governor of all Qi and Blood, with the capacity to interact freely with every form of Qi in the body. San Jiao mediates the relationship between Kidney Jing and Heart Shen. At birth, Lung brings Qi to Kd, Kd grasp it, in the area of Du 4 (mingMen), and this is the begining of San Jiao function – it brings the Fire of Ming Men to the Heart, establishing the foundational relationship Heart–Kidney which is governed through SJ.

The realization of this deep San Jiao function is expressed through Ren Mai points, which facilitate the distribution and integration of Qi and Xue.

By contrast, Chest Qi (Zong Qi) is different in nature and origin.
It is formed through the merging of Da Qi (air) and Gu Qi (food) in the region of the Upper Jiao and primarily supports the Heart and Lungs.
Thus, we can say that Zong Qi is gathered in the Upper Jiao, but it is not the Upper Jiao itself.

On the other hand it is SanJiao that brings yuan Qi from LJiao to lung, and then Gu Qi and da Qi interact. Deep San Jiao function is expressed through the breath.

If there is a stagnation in LJiao , Middle and Upper Jiao can not function, thus we can observe problems in all 3 Jiaos.

As discussed above, San Jiao is a functional system essential for the movement and distribution of Yuan Qi, Yang Qi, and Blood. It mediates between Heart Shen and Kidney Jing and integrates Yin and Yang, as well as Heaven and Earth.
The function of San Jiao arises from the Lower Jiao and unfolds upward through the Middle Jiao to the Upper Jiao, supported by the Ren Mai. Therefore, if the Lower Jiao does not function properly — for example, if there is stagnation — symptoms of deficiency may appear in the Jiaos above. These can include digestive problems (Middle Jiao), cough (when Lung Qi fails to descend), or chest pain, breast problems, and similar conditions (Upper Jiao).
It is also important to remember that the connection between Kidney Jing and Heart Shen can become impaired, leading to psycho-emotional symptoms.
If the Middle Jiao is full, the connection between the Heart and Yi / Earth becomes imbalanced. In this situation, a person may overly focus on intellect and knowledge while lacking intuition and true intelligence, which in turn leads to further stagnation.
If MJiao is weak – there is a weak centre, so again there is no connection between LJiao and UJiao, leading both to emotional problems like anxiety or fear, and poor transformation of food and tiredness.
Pulse diagnosis, together with an understanding of the patient’s constitutional energy, are the primary diagnostic tools. They help us identify which of the three Jiaos is imbalanced, why communication between them is disrupted, and how to treat the condition appropriately.

About points connecting L and U Jiao – try to study points that are located on the abdomen – Ren Mai, Kd, St points – eg Kd 20 , Kd 21, Kd 27, St 25. It depends on what you need to do with the energy. Also the combination of points matters, eg using Ren 4&6 together will send energy from Lower to Upper Jiao. Ren 4 & 14 together strenghen the connectiol between Jing and Shen.