The character 挨 (Āi) is the single most important and most debated character in all of San Yuan Feng Shui. It appears in the term 挨星 (Āi Xīng, "Star Shuffling") — the secret method by which the Nine Stars are mapped onto the 24 Mountains of the Luopan compass.
The standard meaning of 挨 is "to push next to" or "to be adjacent to." In the Xie Zi Fa context, it carries the technical meaning of "sequential proximity" — the process of deriving each star's position by stepping methodically through the hexagram sequence rather than by arithmetic flying (as in standard Fei Xing).
Jiang Dahong deliberately obscured this method in his writings. He declared: "The method of Ai Xing — I dare not speak it plainly, for if the uninitiated hear it, heaven and earth would be shocked" (挨星之法,不敢明言,若為不肖者聞之,天地為之驚駭). This secrecy spawned centuries of competing interpretations.
「挨」 字是整個三元風水中最重要、也最具爭議的一個字。它出現在「挨星」一詞中——即九星映射到羅盤二十四山的秘密方法。
挨的基本含義是「推近」或「相鄰」。在些子法語境中,其技術含義為 「序列推移」 ——不用算術飛行(如標準飛星),而是按卦序逐步推導各星位置。
蔣大鴻在著作中故意隱晦此法。他聲稱:「挨星之法,不敢明言,若為不肖者聞之,天地為之驚駭。」此秘密引發了數百年的爭論。