A trigram is a symbol made up of 3 horizontal lines on top of each other like a hamburger. And according to the I-Ching (book of changes) is the metaphysical model that makes sense out of the universe.
The top line represents heaven, middle line represents earth, and bottom line represents man.
Each line can either be a solid unbroken line (yang) or a broken (yin) line. And the way trigrams are configured with yin and yang lines determine which trigram one represents.
The bagua map consists of the 8 trigrams arranged in a particular order on an octagonal layout. Each trigram is positioned on one side that also depicts the 8 directions.
However, because a house is often shaped in a square, practitioners started to use it in a grid format so that it can be more easily superimposed onto a house plan for better clarity.
Using it in a square grid consisting of 9 smaller grids with nothing in the center then became standard practice.
The 8 trigrams are:
- Kun (坤)
- Sun (巽)
- Li (離)
- Tui (兌)
- Ken (艮)
- Kan (坎)
- Chen (震)
- Chien (乾)
At home, they are used to represent certain members in a household:
- Kun – Mother or matriarch
- Sun – Eldest daughter
- Li – Middle daughter
- Tui – Youngest daughter
- Ken – Youngest son
- Kan – Middle son
- Chen – Eldest son
- Chien – Father or patriarch
The early arrangement of trigrams which follows the He Tu actually indicate a certain period of time as shown in the below table.
| Trigram | Age | Years | Period | Direction |
| Kun | 1 | 18 | 1864 – 1881 | N |
| Sun | 2 | 24 | 1882 – 1905 | S |
| Li | 3 | 24 | 1906 – 1929 | W |
| Tui | 4 | 24 | 1930 – 1953 | SE |
| NA | 5 | 20 | 1944 – 1963 | NA |
| Ken | 6 | 21 | 1954 – 1974 | NW |
| Kan | 7 | 21 | 1975 – 1995 | W |
| Chen | 8 | 21 | 1996 – 2016 | NE |
| Chien | 9 | 27 | 2017 – 2043 | S |
Something to note is that there is no trigram number 5. So the time period in which it occupies overlaps 10 years from the age of 4 and 10 years from the age of 6.
It must also be noted that the trigrams years when used on flying stars feng shui basis is different.
The flying star years and time period has to be taken into account as the later heaven arrangement of trigrams (which will be explained later) follows the flying stars sequence in a grid.
Flying time period is as follows.
| Trigram | Age | Years | Period | Direction |
| Kun | 1 | 20 | 1864 – 1883 | SW |
| Sun | 2 | 20 | 1884 – 1903 | SE |
| Li | 3 | 20 | 1904 – 1923 | S |
| Tui | 4 | 20 | 1924 – 1943 | W |
| NA | 5 | 20 | 1944 – 1963 | NA |
| Ken | 6 | 20 | 1964 – 1983 | NE |
| Kan | 7 | 20 | 1984 – 2003 | N |
| Chen | 8 | 20 | 2004 – 2023 | E |
| Chien | 9 | 20 | 2024 – 2043 | NW |
When determining the age of a house, if one is using the bagua trigrams, it might result in a different age than one using flying stars.
For example, the year 2018 would be an age of 9 house according to trigrams, but age of 8 according to flying stars.
4 trigrams at the cardinal directions also make up part of the 24 mountains.
They have the following elemental base which follows the Luo Shu relation to the later heaven arrangement:
- Kun – Earth
- Sun – Wood
- Li – Fire
- Tui – Metal
- Ken – Earth
- Kan – Water
- Chen – Wood
- Chien – Metal
In the broader study of Yi Jing, they symbolize:
- Kun – Earth
- Sun – Wind
- Li – Fire
- Tui – Lake
- Ken – Mountain
- Kan – Water
- Chen – Thunder
- Chien – Heaven
They are also associated with the following body parts.
- Kun – Flesh, stomach, abdomen, spleen, reproductive organs
- Sun – Arms, thighs, buttocks, hips
- Li – Heart, eyes, blood
- Tui – Mouth, throat, tongue, teeth, chest
- Ken – Fingers, bone, back, nose, toes
- Kan – Ears, kidneys, blood
- Chen – Liver, hair, foot
- Chien – Head, lungs, bone
These information is often used in the practice of feng shui to identify the energy source that causes health problems.
For example, if a person has constant back pain and spine issues, then a feng shui practitioners might zero in on what is the situation at the northeast of the house. This is because the back is associated with the Ken trigram, which is represented by the northeast direction on the later bagua.
We can also link the trigrams to a wide spectrum of colors.
- Kun – Black, yellow
- Sun – Green, white
- Li – Red
- Tui – White
- Ken – Yellow
- Kan – Black
- Chen – Green
- Chien – White, gold, silver
It should be noted that the practice of feng shui often uses a mixture of different concepts that include the trigrams. Thus, the colors associated with trigrams i practice can often be linked to the colors of directions, elements and lou shu.
Trigram arrangement
There are 2 ways the trigrams are arranged to make up the bagua. Actually there are more than 2. It’s just that only 2 are used in modern practice.
- Early heaven arrangement
- Later heaven arrangement
The early arrangement is used for yin purposes like the feng shui of grave sites for the blessing of ancestors to descendants.
The later arrangement is for yang purposes like feng shui for the house of the living.
From this point of view, if a feng shui practitioner uses the early arrangement for the feng shui of your house, you would know that he has either made a mistake or doing so intentionally for a specific purpose.
Otherwise, the later arrangement of trigrams is always used for the feng shui of homes, buildings, apartments, etc.
As the later arrangement is related to flying stars, it is implied that when using a feng shui bagua map for a house, the basics of flying star feng shui has to considered as well.
