What are Chinh Than and Linh Than?
Chinh Than is the direction currently in period, meaning the direction tied to the star ruling the present period. Linh Than is the palace directly opposite Chinh Than through the center, meaning the direction whose period has passed and which carries declining qi. According to Shen Zhu Reng in Trach van tan an, citing Jiang Da Hong in Duong trach chi tien: at the Chinh Than direction one should open a door to receive qi and avoid seeing water, while at the Linh Than direction one should see water and avoid opening a qi-receiving door. This is the root rule for understanding why the same body of water is good in one direction and harmful in the other.
Four concepts are often confused: the Chinh Than direction, the Linh Than direction, Chinh Thuy and Linh Thuy. The Chinh Than direction is the current-period direction; the Linh Than direction is the out-of-period direction. But water placed at the Chinh Than direction is called Linh Thuy, because it falls where qi is prosperous and therefore works against itself. Water placed at the Linh Than direction is called Chinh Thuy, because that position is declining, and water takes the declining place as its prosperous place. In other words, the names run opposite to the direction names on purpose, to remind students that water and qi move in two different directions.
Shen Zhu Reng also notes that at the Chinh Than direction, seeing water indicates missing the period, losing the period, and losing wealth. At the Linh Than direction, seeing a river, sea, pond or lake means that water is considered prosperous water for money. This is the conventional language of the Huyen Khong school, not an absolute statement about the finances of any particular family, because it must still be set within the whole flying star chart, the landform, and the time.
Why is it called Linh Thuy and not Chinh Thuy?
Shen Zhu Reng raises this question directly in Trach van tan an, and he himself notes that many students still find it paradoxical. The explanation lies in the words Chinh and Linh. Chinh Than is qi in the right period; Linh Than is qi that has missed the period. Water does not behave like qi: it needs a declining place to function, and in a prosperous place it is suppressed. So water at the Linh Than direction is called Chinh Thuy, meaning water in the right period, while water at the Chinh Than direction is called Linh Thuy, meaning water that has missed the period.
It must be stressed that water here means real landscape water: rivers, seas, ponds, lakes, and flows around the land. It is not an aquarium added inside the house, and not a small rockery. Shen Zhu Reng states clearly that the Linh Than direction should see rivers, seas, ponds and lakes, meaning forms of water with real volume and flow. Placing a small basin of water indoors does not create Linh Thuy in this sense, and cannot replace the landform of the site.
Table of Chinh Than and Linh Than across the nine periods
Chinh Than and Linh Than change with each period. The opposite palace is calculated by adding the two positions to make 10, meaning the opposite palace in the bagua. The table below summarizes the current-period direction and the opposite direction for the nine periods.
| Period | Chinh Than (current-period direction) | Linh Than (opposite direction) |
|---|---|---|
| 1 | North (Kham) | South (Ly) |
| 2 | Southwest (Khon) | Northeast (Can) |
| 3 | East (Chan) | West (Doai) |
| 4 | Southeast (Ton) | Northwest (Can) |
| 5 | Center palace | Center palace |
| 6 | Northwest (Can) | Southeast (Ton) |
| 7 | West (Doai) | East (Chan) |
| 8 | Northeast (Can) | Southwest (Khon) |
| 9 | South (Ly) | North (Kham) |
Period 5 is a special case because the number 5 enters the center palace and has no opposite direction in the usual sense, so many books do not build a table for this period and handle it separately. In Trach van tan an, Shen Zhu Reng writes clearly: period 7 takes West as Chinh Than, so one should open a door at West; it takes East as Linh Than, so one should look out onto rivers, seas, ponds and lakes. The table above matches that record.
What is Thanh Mon and why is it needed?
In feng shui qi theory, Thanh Mon is understood as the place through which qi from the outside environment is led into an area, and that area may be a burial site, a dwelling site, or a building. Tuyen tap bai viet Phong Thuy chon loc so 4 likens Thanh Mon to the throat of a living body, because this place determines circulation and life qi. When the main facing of a house is not favorable to the period, people look for another palace to serve as a secondary door or qi-leading path, and that palace is called Thanh Mon.
Tuyen tap bai viet Phong Thuy chon loc so 4 divides Thanh Mon into primary and secondary. Primary Thanh Mon is the place with the highest harmony of qi theory and landform, and has the strongest effect. Secondary Thanh Mon plays a supporting role, weaker in force but still able to gather life qi. Tuyen tap bai viet Phong Thuy chon loc so 3 adds a third type, the hidden Thanh Mon, meaning a type not expressed by a visible door or path. So even in the number and names of Thanh Mon types, the sources are not fully agreed.
Conditions for a palace to be used as Thanh Mon
According to Tuyen tap bai viet Phong Thuy chon loc so 4, when considering the main gate position of a yang dwelling, if the two flanking palaces share the same original dragon as the main gate facing and form a Ha Do number combination such as 1-6, 2-7, 3-8 or 4-9, that palace is considered primary Thanh Mon. Conversely, palaces that do not form this combination are called secondary Thanh Mon. The second condition is that the period star at that palace must be usable, meaning it must fall into a favorable flying case, not that any palace can be used.
Tuyen tap bai viet Phong Thuy chon loc so 4 gives a specific example for period 1 with Ton mountain and Can facing: the Kham palace is a place that could serve as Thanh Mon, but the period star at Kham is Luc Bach, which is not the ruling star, so this configuration cannot use the Thanh Mon formula, and applying it would lead to ruin. When period 2 begins, That star arrives at Kham; That in the heaven cycle enters the center, is a yin star and so flies in reverse, causing Nhi Hac to arrive at Kham; only then can Thanh Mon be used. This example shows that the same palace and the same house facing can reverse conclusions across periods.
How do Huyen Khong schools differ in determining Thanh Mon?
This is where it must be stated clearly that there is no single way of determining Thanh Mon accepted by all schools. Tuyen tap bai viet Phong Thuy chon loc so 4 follows the direction of the two flanking palaces sharing the same original dragon as the main gate facing, then filters further by the Ha Do combination. Some other schools accept only the two palaces adjacent to the facing, meaning the two palaces immediately to the left and right of the main facing, and do not extend to the whole chart. Still other schools consider Thanh Mon by the relationship between the period star and the original dragon of the palace, independent of the position adjacent to the facing.
This difference leads to different practical results: for the same house, two masters from two schools may point to two different Thanh Mon palaces, and therefore propose two different secondary door positions. Readers should know that this is a real disagreement within the tradition, not one side right and one side wrong. This article presents the direction of Tuyen tap bai viet Phong Thuy chon loc so 4, meaning the method of considering the two flanking palaces with the same original dragon and then filtering by the Ha Do combination, and notes that the method of accepting only the two palaces adjacent to the facing also exists in parallel.
How does Thanh Mon rescue a house with thuong son ha thuy?
Thuong son ha thuy is a configuration in which both the facing star and the mountain star fall into unfavorable positions: the mountain star cannot reach a place with a mountain or high block, and the facing star cannot reach a place with water. The result is that the house loses both people and wealth in the conventional language of the Huyen Khong school. Thanh Mon is then used as an escape: instead of receiving qi through the main facing, which is already broken, people look for another palace with a usable period star to serve as a door or qi-leading path.
However, it must be said at once that Thanh Mon is not a universal cure. Tuyen tap bai viet Phong Thuy chon loc so 4 states clearly that if the palace intended as Thanh Mon does not have the ruling star, applying the Thanh Mon formula will lead to ruin, meaning worse than leaving it alone. In other words, Thanh Mon can only rescue when the conditions of original dragon, Ha Do combination and period star are all met. Without the conditions, one should not open a door according to Thanh Mon.
As for landform, Thanh Mon needs a real path, with real foot traffic or real qi flow passing through, not a door drawn on a plan. This is the point that both Tuyen tap bai viet Phong Thuy chon loc so 4 and Tuyen tap bai viet Phong Thuy chon loc so 3 stress: Thanh Mon is where qi truly enters, so if there is no real path, that palace does not function as Thanh Mon no matter how beautiful the calculation.
Water and doors here mean real water and real doors
A common misunderstanding turns these concepts into decorations. Water in Linh Thuy means rivers, seas, ponds and lakes, meaning forms of water with volume and flow, not an aquarium placed in the living room. A door in Chinh Than means a qi-receiving door, meaning a real passage through which people and qi move, not a small window that is always closed. When Shen Zhu Reng writes that at the Chinh Than direction one should open a door to receive qi, he is speaking of a door used for qi to enter, not of hanging some object.
The same applies to Thanh Mon. Tuyen tap bai viet Phong Thuy chon loc so 4 speaks of the main path leading into the center of the house or land, meaning a real path. If the house has no path at that palace, then that palace cannot serve as Thanh Mon, regardless of the calculation.
Points on which the sources do not agree
Beyond the disagreement over how to determine Thanh Mon already noted, there is also disagreement over the number of Thanh Mon types: Tuyen tap bai viet Phong Thuy chon loc so 4 says two types, primary and secondary, while Tuyen tap bai viet Phong Thuy chon loc so 3 says three types, primary, secondary and hidden. For period 5, books also handle it differently: some build a separate table, some merge it into the center palace and assign no opposite direction. On the degree of effect of secondary Thanh Mon, according to Tuyen tap bai viet Phong Thuy chon loc so 4, though weaker than primary Thanh Mon, it can still gather life qi; by contrast, Tuyen tap bai viet Phong Thuy chon loc so 3 emphasizes more, holding that secondary Thanh Mon plays an important role when the main facing is not truly prosperous in qi.
Readers should approach the tables and rules above as a system of conventions with its own internal logic, not as a formula producing a fixed result for every house. Application still depends on the specific flying star chart, the real landform of the site, and the time of consideration, so conclusions of good or bad fortune should be taken as reference only.
