Gen Mountain Direction in the 24 Mountain Directions of Feng Shui - Meaning and Interpretation

Where does the Can Mountain sit on the luopan, and why is its position derivable rather than memorised?

The Can Mountain occupies roughly 37.5° to 52.5° on the luopan ring, counted clockwise from 0° at due North. This is the fourth mountain among the 24, sitting in the middle of the Northeast direction.

This position does not need to be memorised, because it can be derived from two simple rules. First, the 24 mountains divide the 360° of the luopan evenly, each mountain spanning exactly 15°. Second, the mountain at the exact centre of each of the eight 45° directions carries that direction's name. The Northeast direction runs from 22.5° to 67.5°, so its central mountain occupies 37.5° to 52.5°, and carries the name Can.

To check this, simply count: start from Ty at 0°, adding 15° at each step. The first mountain is Ty (0° to 15°), the second is Quy (15° to 30°), the third is Suu (30° to 45°... wait, counting this way gives a different result). In fact the correct way to count is: Ty sits at the exact centre of North, meaning 352.5° to 7.5°. From there add 15° clockwise: Quy (7.5° to 22.5°), Suu (22.5° to 37.5°), Can (37.5° to 52.5°), Dan (52.5° to 67.5°). So Can is indeed the fourth mountain, and its position matches the fact table.

Which palace does the Can Mountain belong to in the Later Heaven bagua, and which three mountains share that palace?

The Can Mountain belongs to the Can palace in the Later Heaven bagua. The three mountains in the Can palace, in the order Earth nguyên long, Heaven nguyên long, Human nguyên long, are Suu, Can and Dan.

It is necessary to distinguish clearly between palace and direction, because this is where many articles get confused. A direction is a 45° position on the luopan, while a palace is one of the eight trigrams of the Later Heaven bagua assigned to that position. The Northeast direction and the Can palace correspond to the same 45° span, but are named differently depending on the frame of reference: saying "Northeast direction" is speaking in terms of the eight geographic directions, saying "Can palace" is speaking in terms of the bagua. In this article, every mention of a palace refers to the Can palace, no other palace.

The three mountains in the Can palace cannot substitute for one another, because each mountain corresponds to a different nguyên long, and the nguyên long determines how the flying stars enter the central palace in Xuan Kong. Suu is Earth nguyên long, Can is Heaven nguyên long, Dan is Human nguyên long. When constructing a star chart, the same Northeast direction but with the sitting mountain at Suu, Can or Dan will yield a different yin-yang for the mountain, which in turn changes the flight direction of the mountain star, and produces a different interpretation. That is why the three mountains cannot be lumped together as one.

What is the Five Elements nature of the Can Mountain, and why are there two answers that do not contradict each other?

Considering the Five Elements of the earthly branch or heavenly stem that itself carries the mountain's name, Can is one of the four trigrams Qian Kun Can Xun that are brought into the 24 mountain ring, and the Can trigram belongs to the Earth element. Considering the palace that contains it on the Later Heaven luopan, Can sits within the Can palace, and the Can palace also belongs to the Earth element. For the Can Mountain, the two answers coincide, both being Earth.

But even when they coincide, the frame of reference must still be stated clearly, because for many other mountains they do not coincide. Take the Dan mountain: considering the Five Elements of the earthly branch Dan, it belongs to Wood, but considering the palace that contains it, Dan sits within the Can palace which belongs to Earth. These two statements do not contradict each other because they speak of two different things: one speaks of the element of the earthly branch itself, the other speaks of the element of the palace in which that earthly branch resides.

An article that writes "mountain X belongs to the Earth element" and a few lines later writes "mountain X belongs to a palace of the Wood element" without declaring the frame of reference will make readers think there is a contradiction. The correct way to write is always to attach the prefix: "considering the Five Elements of the earthly branch, ..." or "considering the palace that contains it on the Later Heaven luopan, ...".

What is the Three Yuan long of the Can Mountain, and what does that mean when choosing a mountain direction?

The Can Mountain belongs to the Heaven nguyên long. Among the three mountains in the Northeast direction, Suu is Earth nguyên long, Can is Heaven nguyên long, Dan is Human nguyên long.

The significance of this classification lies in the fact that it governs how the flying stars enter the central palace in Xuan Kong. Each nguyên long has its own yin-yang rule, and that rule determines whether the mountain star flies forward or backward. The Heaven nguyên long Can is placed in the yang group in many branches of Xuan Kong, but as will be discussed in the section below, there is disagreement on this point among the schools.

The three mountains within one palace cannot substitute for one another because each mountain carries a different nguyên long. If one mistakes Suu for Can, even though both lie within the Can palace, the resulting star chart will differ. This is why when measuring a house's direction, an error of a few degrees can push from Heaven nguyên long to Earth nguyên long or Human nguyên long, changing the entire interpretation that follows.

Where does Bát Trạch place the Can Mountain, and what are the limits of that placement?

In Bát Trạch, the Can palace belongs to the West Four Houses, in the same group as the Qian palace, the Kun palace and the Dui palace. A person whose life trigram falls in the West Four Life group is considered compatible with a house whose sitting or facing lies at the Can palace.

This placement has clear limits. Bát Trạch only divides the eight palaces, not the 24 mountains, so it does not distinguish Suu, Can and Dan. Saying "a house sitting at the Can Mountain" in Bát Trạch actually only means "a house sitting at the Can palace", and every mountain within that palace is treated alike. This is the fundamental difference from Xuan Kong, where the three mountains within the same palace yield different results.

Another limit: Bát Trạch is a system used to match a life trigram with a house direction, not to interpret a sitting mountain according to the 24 mountains. So when an article says "Bát Trạch places the Can Mountain in the West Four Houses", it should be understood as placing the Can palace, and the Can Mountain lies within that palace so it follows along.

How does Xuan Kong flying stars use the Can Mountain, and where do the schools not yet agree?

In Xuan Kong flying stars, the Can Mountain is used to construct a star chart according to the period, with the mountain star and facing star flying according to the yin-yang rule of the nguyên long. The Can Mountain belongs to the Heaven nguyên long, and in many branches of Xuan Kong, the Heaven nguyên long is placed in the yang group.

Where the schools have not agreed lies in how yin-yang is assigned to each mountain. Some branches assign yin-yang according to the nguyên long, some assign according to the heavenly stem or earthly branch, and the results can differ for certain mountains. For the Can Mountain, most branches place it as yang, but a researcher needs to know that this is a point of disagreement within the tradition, not an absolute rule on which every school agrees.

One point to avoid: one should not write "according to the Three Yuan school, the Can Mountain belongs to a different trigram". The palace of the Can Mountain in the Later Heaven bagua is the Can palace, and no feng shui school uses a different system for dividing the 24 mountains. Disagreement between schools, if any, lies in how yin-yang is assigned and how the flying stars are calculated, not in how the palaces are divided.

How does measurement error affect the determination of the Can Mountain?

Each mountain is only 15° wide, so a slight deviation crosses into another mountain. The Can Mountain runs from 37.5° to 52.5°. At the lower end, below 37.5° is the Suu mountain (22.5° to 37.5°). At the upper end, above 52.5° is the Dan mountain (52.5° to 67.5°).

The two marks 37.5° and 52.5° are hard boundaries. Measuring 37.4° already crosses into Suu, measuring 52.6° already crosses into Dan. Since Suu is Earth nguyên long while Dan is Human nguyên long, drifting to either side will change the nguyên long of the mountain, which in turn changes how the star chart is constructed in Xuan Kong.

In practical measurement, one should measure several times, at several positions, avoiding interference from metal and electronic devices. An error of one or two degrees is common, and with a mountain 15° wide, one or two degrees can be enough to push into the neighbouring mountain.

Which parts of this article are cultural knowledge, not prediction?

This entire article is cultural knowledge. The division of the 24 mountains, the assignment of Later Heaven bagua palaces, the classification of Earth, Heaven and Human nguyên long, the placement of the West Four Houses according to Bát Trạch, and the flying star rules according to Xuan Kong are all theoretical systems recorded within the Eastern feng shui tradition.

This article offers no prediction about anyone's wealth, health or destiny. Numbers such as 37.5° and 52.5°, names such as the Can palace or Heaven nguyên long, are all conventions of a knowledge system, not claims about outcomes that will occur in life.

Readers who wish to apply this in practice should regard it as a way of observing and organising space according to tradition, not as a tool of prediction. Its value lies in helping one understand a part of Eastern thinking about direction and time, not in promising anything.

Overview article on the topic: What is feng shui? Foundational principles and how to apply it