相傳先天八卦為伏羲氏所創，所以先天八卦圖又稱作伏羲八卦圖。伏氏按大自然變化，循人類生活狀態中創劃出來的。

即乾南坤北，離東坎西震居東北，巽居西南，艮居西北，兌宮東南。此即夫婦正對之意。乾為父，坤為母，父母南北相對；震長男，巽長女，長男配長女；坎中男，離中女，東西正配；艮少男，兌少女，少男配少女，西北對東南。亦即乾為天，坤為地，震為雷，巽為風，坎為水，離為火，艮為山，兌為澤。乾坤相對，天地定位。震巽相對，風雷薄；艮兌相稱，山澤同氣，坎離相，為水火不相射。

據文獻記載周文王被紂王軟禁時期，在羑里獄中；把先天八卦復位，再以四方八向為經緯，定出“後天八卦圖”故亦稱文王八卦。

“先天八卦”是以天地上下為體。“後天八卦”則以四方定位為用，故風水，命理五行，幾乎都以後天八卦的排列方位來使用的。

Former Heaven and Latter Heaven arrangements of the eight trigrams

It was believed that Emperor Fu Xi devised the Former Heaven arrangement of the eight trigrams, and it was also called the Fu Xi’s eight trigram arrangement. The arrangement was created according to the human living at that time and the changes observed in the environment.

Trigram-Qian is located in the south. Trigram-Kun is located in the north. Trigram-Li is located in the east; Trigram-Kan is in the west. Trigram-Zhen resides in northeast; Trigram-Sun resides in southwest. Trigram-Gen resides in northwest; Trigram Dui resides in southeast. It suggests the coupling of husband and wife.

Trigram-Qian is referred to as father, Trigram-Kun, as mother. Father and mother are on either side in the south and north. Trigram-Zhen is referred to as the eldest son; Trigram-Sun as the eldest daughter. Eldest son is pairing up with the eldest daughter. Trigram-Kan is referred to as the middle son; Trigram-Li, as middle daughter.

East and west match with one another. Trigram-Gen is referred to as the youngest son; Trigram-Dui, as the youngest daughter. As the youngest son matches with the youngest daughter, northwest is facing southeast on the opposite side.

Trigram-Qian is also referred to as the heaven. Trigram-Kun is referred to as earth. Trigram-Zhen is referred to as thunder. Trigram-Sun is referred to wind. Trigram-Kan is referred to as water. Trigram-Li is referred to as fire. Trigram-Gen is referred to as mountain. Trigram-Dui is referred to as marsh.

Qian and Kun are on opposite sides, and they become the heaven and earth. Zhen and Sun oppose each other; thunder and wind press upon and cover one another. As Gen and Dui match each other, the mountain and marsh communicate vital breath. As Kan and Li are mutually generating and destroying, fire and water do not disgust with each other.

According to ancient literature, when Emperor Wen of Zhou dynasty was put to solitary confinement, he revised the arrangement of the eight trigrams in Former Heaven Sequence, and derived the Latter Heaven Eight Trigram Arrangement. So, it is also called the Emperor Wen’s Eight Trigram Sequence.

The Former Heaven eight trigram arrangement illustrates the laws concerning heaven and earth and it forms the principal foundation. On the other hand, the Latter Heaven eight-trigram arrangement utilizes the four directions in fixing positions. Therefore, the Latter Heaven eight-trigram arrangement is more applicable in the practice of feng shui, destiny and five-element determination.