TL;DR: Thủy khẩu is the water gate, where a flow gathers and exits the area of a formed huyệt (dragon point), seen in classical feng shui as the lock that holds the energy of the whole site. The saying 'heaven gate open, earth door closed' means the place where water flows in (the heaven gate) should be wide open, while the place where water flows out (the earth door, that is, the thủy khẩu) should be closed and winding, so energy gathers and does not scatter.
What Is Thủy Khẩu?
Thủy khẩu is the water gate, the place where a watercourse gathers and then exits the area where the long mạch (dragon vein) forms a huyệt (dragon point). In classical geography, thủy khẩu is not merely where a river passes but the locking point that holds the energy of an entire site, like the gate of a citadel. The book Nhập môn loan đầu calls thủy khẩu the crucial point and quotes the feng shui master: 'Do not fear sand flying or water rushing; what matters is la tinh locking the thủy khẩu.' That means even if the mountain forms look scattered, as long as the water gate is tightly locked, a huyệt can still form.
According to the book Phong thủy cổ đại Trung Quốc: lý luận và thực tiễn, volume 2, thủy khẩu is divided into đại thủy khẩu (also called chính thủy khẩu) and tiểu thủy khẩu. Đại thủy khẩu is the common water gate of the whole region, while tiểu thủy khẩu is the water gate of each individual long and huyệt. The ancients said to find the small watercourse within the large one, meaning đại thủy khẩu gives rise to tiểu thủy khẩu.
What Does 'Heaven Gate Open, Earth Door Closed' Mean?
Thiên môn is the heaven gate, địa hộ is the earth door. In the common reading of the Loan Đầu school, thiên môn is where water flows into the site, and địa hộ is where water flows out, that is, the thủy khẩu itself. 'Heaven gate open' means the incoming water should be wide and unobstructed; 'earth door closed' means the outflow should be narrow and winding, locked by hills or rocks, so energy does not leave with the water. The saying describes the ideal landform: incoming water must flow freely, outgoing water must be closed off.
However, the specific understanding of these two gates is not uniform among schools. The book Địa lý Nguyên Không Pháp Giám by Liên Trì tiên sinh defines thủy khẩu according to kim long (metal dragon) and nguyên vận (period cycles): thủy khẩu changes with the kim long. When the kim long moves, the mountain becomes Càn, the direction becomes Khôn. In the current period, Đoài and Tốn are chosen as thủy khẩu; in a non-current period, Chấn and Cấn are chosen. The book also records: 'Water flowing on the left is the thuận cục (forward configuration), using Đoài; Đoài reversed becomes Tốn, so water flowing on the right is the nghịch cục (reverse configuration), using Tốn.' Thus, in the Nguyên Không school, thủy khẩu is not fixed but changes with the period and the direction of water flow.
In contrast, the Loan Đầu school emphasizes landform. The book Nhập môn loan đầu describes forms of locking the thủy khẩu such as Bắc thần tỏa thủ (North Star locking hand), Hãn môn (Sweat Gate), and La tinh (Net Star). Bắc thần tỏa thủ is a large independent mountain locking the thủy khẩu, indicating great nobility, often producing emperors. Hãn môn is two mountains facing each other at the thủy khẩu, both standing independently, not connected to any other sand mountain. La tinh is a small isolated mountain at the thủy khẩu, which should be round and still to be auspicious; it is a noble configuration like a golden seal or jade seal.
How Do Different Feng Shui Schools Define Thủy Khẩu?
The difference between schools lies in whether they emphasize landform or li qi (energy patterns). The book Nhập môn loan đầu has a passage: 'Use li qi to discuss the auspiciousness or inauspiciousness of thủy khẩu,' emphasizing that even if sand flies and water rushes, as long as la tinh encircles and locks the thủy khẩu, the huyệt can still form. This school considers the landform of rocks and sand mounds around the water gate as the decisive factor.
Meanwhile, the book Địa lý Nguyên Không Pháp Giám places heavy emphasis on period energy and gua principles. It states clearly: 'One water gate gua is divided into two poles. Water flowing on the left is the thuận cục, using Đoài. Đoài reversed becomes Tốn, so water flowing on the right is the nghịch cục, using Tốn. In the original period, Chấn is used for the thuận cục. Chấn reversed becomes Cấn, so the nghịch cục uses Cấn. The four cardinal directions of Đoài are all on the right. The four corners of Đoài are all on the left.' Thus, the same water gate is assigned different gua depending on flow direction by the Nguyên Không school, and auspiciousness or inauspiciousness is judged accordingly.
The book Phong thủy cổ đại Trung Quốc: lý luận và thực tiễn, volume 2 adds that thủy khẩu has main and secondary configurations. In the main configuration, the two sides of the sand landform at the thủy khẩu embrace each other; in the secondary configuration, the upper face of the sand landform curls inward while the lower face converges. Whether main or secondary, the sand at the thủy khẩu must have a segmented or still form to be considered noble.
La Tinh Locking Thủy Khẩu and Other Water-Locking Forms
La tinh is the most common form of locking the thủy khẩu. The book Nhập môn loan đầu defines: 'A small isolated mountain at the thủy khẩu is la tinh locking the thủy khẩu.' Its shape should be pointed or round to be auspicious, indicating the emergence of nobility. La tinh needs to be round and still to be auspicious. La tinh is a golden seal or jade seal, a noble configuration.
Besides la tinh, there are other forms. Bắc thần tỏa thủ is a large independent mountain locking the thủy khẩu, indicating great nobility, often producing emperors. Bắc thần often has symbolic forms such as towers, palaces, heavenly horses, lions, and elephants. Hãn môn is two mountains facing each other at the thủy khẩu, serving to enclose the mountain pass and water gate. The sand mountains of Hãn môn should be pointed, round, and independent to be auspicious.
The book Phong thủy cổ đại Trung Quốc: lý luận và thực tiễn, volume 2 further states: 'To find a good mountain for burying kings and lords, there must be a Bắc thần Tôn tinh guarding the Thủy Khẩu, towering unusually, inspiring awe from afar, and only then is it called a superior configuration.' This shows that thủy khẩu is not only a water exit but also a point where spiritual energy gathers, needing to be guarded by special mountain forms.
Application of Thủy Khẩu in Yang Dwellings and Yin Dwellings
In yin dwellings (burial sites), thủy khẩu determines the gathering or scattering of energy. The book Nhập môn loan đầu records: 'When the long stops truly, the thủy khẩu and all sand mountains embrace and protect. All watercourses return to the path, and the left and right sand mountains also stop. If the mountain form has not yet stopped, the watercourse will also follow and leave; the gate cannot enclose, the la city cannot protect, and mountains and water cannot meet.' Therefore, thủy khẩu is the meeting point of the long mạch and the watercourse, where energy stops to form a huyệt.
In yang dwellings (houses), thủy khẩu is understood more broadly, including water gates, drains, and ponds around the house. The book Nhập môn loan đầu quotes the feng shui master: 'Do not fear sand flying or water rushing; what matters is la tinh locking the thủy khẩu.' For houses, if the water gate is closed, even if the landform seems less than ideal, misfortune can turn to fortune. The book also notes about the location of water taps and ponds in the house: 'In directions where the mountain plate star is prosperous, avoid water; encountering water often causes loss of people. In directions where the mountain plate star is declining or dying, encountering water can turn misfortune into fortune.'
Table Classifying Thủy Khẩu According to Classical Books
| Type of thủy khẩu | Landform characteristics | Auspicious or inauspicious meaning | Source |
|---|---|---|---|
| La tinh | Small isolated mountain at the water gate, round, still | Auspicious, indicates nobility, golden seal and jade seal | Nhập môn loan đầu |
| Bắc thần tỏa thủ | Large independent mountain locking the water gate, with forms of towers, lions, elephants | Great nobility, can produce emperors | Nhập môn loan đầu |
| Hãn môn | Two mountains facing each other, independent, not connected to other sand mountains | Auspicious if pointed, round | Nhập môn loan đầu |
| Đại thủy khẩu | Common water gate of the whole region | Chính thủy khẩu, determines the energy of the whole site | Phong thủy cổ đại Trung Quốc, volume 2 |
| Tiểu thủy khẩu | Water gate of each individual long, huyệt | Depends on đại thủy khẩu | Phong thủy cổ đại Trung Quốc, volume 2 |
| Thủy khẩu according to Nguyên Không | Changes with kim long and period, thuận cục uses Đoài, nghịch cục uses Tốn | Auspiciousness depends on period and gua | Địa lý Nguyên Không Pháp Giám |
Why Is Thủy Khẩu More Important Than the Long Mạch?
The book Nhập môn loan đầu has a saying: 'Sand flies, water rushes, only la tinh encircling and locking the thủy khẩu is needed.' As long as the thủy khẩu is tight, even if sand flies and water rushes, a huyệt can still form. This shows that in the view of the Loan Đầu school, thủy khẩu is the final decisive factor. No matter how majestic the long mạch, if the water gate is not closed, energy will scatter and no huyệt can form.
The book Phong thủy cổ đại Trung Quốc: lý luận và thực tiễn, volume 2 explains: 'Thủy Khẩu and the landform of Sand are extremely closely related, so their skillful combination is also called chuyên kết (special knot).' Chuyên kết here means that whether it is a Tiểu Thủy Khẩu or Trung dương, Ngoại dương, it is best to have many layers of Sand forms knotting around. Thanks to this, water becomes clear and sand embraces, taking the Thủy Khẩu as the crucial gate guarding the strategic area, and the feng shui of the burial site will surely change for the better.
Gợi ý của Nhật Nguyệt
When reading classical books on thủy khẩu, learners should clearly distinguish two layers: the landform layer (loan đầu) and the li qi layer (nguyên không, phi tinh). For the same water gate, the Loan Đầu school may judge auspiciousness based on the shapes of rocks, while the Nguyên Không school judges by period and gua. No school is absolutely correct; it depends on the case and purpose. For modern yang dwellings, the concept of thủy khẩu can be applied to arranging water gates, drains, and ponds so that incoming energy is open and outgoing energy is closed, but one should not mechanically apply ancient yin dwelling configurations to houses. This is the interpretation of Nhật Nguyệt, not a mandatory recommendation.
