乾卦是什麼意思？易經第一卦的卦辭與六爻白話解說
作者：Wei Chun Chuang・2026-11-05
乾卦是易經六十四卦的第一卦，也是最常被問到的一卦。它六爻全是陽爻，上下卦都是乾，所以全名叫「乾為天」。這篇用白話一句一句解說乾卦的原文。
乾卦長什麼樣子？
乾卦是六條完整的陽爻疊在一起，上卦是乾 ☰、下卦也是乾 ☰。乾的自然象是天，特性是「健」，也就是剛強、持續運行不停。
它的對面是坤卦：六爻全陰，象徵地與柔順。乾坤兩卦常被看成整本易經的起點。
卦辭「元亨利貞」是什麼意思？
乾卦的卦辭只有四個字：「元亨利貞」。一個常見的白話理解是：
- 元：開始、根本。
- 亨：通達、順暢。
- 利：適宜、有收穫。
- 貞：守正、堅定。
〈文言傳〉把這四個字說成四種德行。也有學者認為最早的意思比較接近「大為亨通，利於守正」。兩種讀法都常見，初學時先抓住「有好的開始，能通達，但要守正」這個大意即可。
六條爻辭在說什麼？
乾卦的六爻用一條龍從潛藏到飛天、再到過頭的過程，描寫一件事從開始到極點的變化。爻名裡的「九」代表陽爻，「初、二、三、四、五、上」是位置，由下往上。
- 初九：「潛龍勿用」。龍還藏在水裡，時機未到，先別急著行動，累積實力。
- 九二：「見龍在田，利見大人」。龍出現在田野，開始被看見，適合去見能指點你的人。
- 九三：「君子終日乾乾，夕惕若厲，无咎」。整天努力不懈，到晚上仍保持警惕，雖然處境有危險，卻不會出錯。
- 九四：「或躍在淵，无咎」。龍準備從深淵躍起，可以試著往上，也可以退回，看清時機就沒有過錯。
- 九五：「飛龍在天，利見大人」。龍飛上天，是最好的位置，能發揮所長。
- 上九：「亢龍有悔」。龍飛得太高、過了頭，會有懊悔。提醒盛極要懂得收斂。
「用九」是什麼？
乾卦多了一段「用九」：「見群龍无首，吉」。看見一群龍，卻沒有一條爭著當首領，這樣是吉。常見的解釋是：剛強的力量不爭先、不逞強，反而好。用九只出現在乾卦，坤卦則有對應的「用六」。
「天行健，君子以自強不息」出自哪裡？
這句出自乾卦的〈象傳〉，也就是〈大象〉。意思是：天的運行剛健不停，君子看到這個現象，也要自己努力、不停止。這句話後來成為很常見的座右銘。
讀乾卦可以學到什麼？
乾卦的六爻很適合當成一個「時機」的練習：現在的處境比較像潛藏、剛被看見、努力中、準備跳躍、正得位，還是已經過頭？用這個角度讀，比把它當成好運壞運的判斷更有用。
常見問題
- 乾卦是好卦嗎？
- 乾卦的卦辭是「元亨利貞」，整體偏正面，但上九「亢龍有悔」也提醒過頭會後悔。易經的每一卦都同時有順境與提醒，不適合只用好壞判斷。
- 「潛龍勿用」是什麼意思？
- 龍還潛藏在水中，時機未到，先不要急著行動，適合充實自己、等待時機。
- 「九五之尊」和乾卦有關嗎？
- 有。九五是乾卦第五爻「飛龍在天」，第五爻常被看成卦中最尊的位置，後來「九五之尊」就用來指帝位。
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What does the Qian hexagram mean? The first hexagram of the I Ching in plain words
By Wei Chun Chuang・2026-11-05
Qian is the first of the sixty-four hexagrams and the one people ask about most. All six lines are yang and both trigrams are Qian, so its full name is "Qian is Heaven". This article explains its text line by line in plain words.
What does Qian look like?
Six solid yang lines: Qian ☰ above and Qian ☰ below. The trigram's image is heaven and its quality is strength that keeps moving without stopping.
Its counterpart is Kun, six yin lines, the image of earth and receptiveness. The two are often treated as the starting point of the whole book.
What does the judgment "yuan heng li zhen" mean?
Qian's judgment is four characters. A common plain reading:
- Yuan: origin, what is fundamental.
- Heng: getting through, flowing freely.
- Li: fitting, beneficial.
- Zhen: correct and steadfast.
The Words of the Text commentary reads them as four virtues. Some scholars think the earliest sense was closer to "great success; it is favourable to stay steadfast". Both readings are common; as a beginner, keep the gist: a good beginning that goes through, as long as you stay on course.
What do the six lines say?
The lines follow a dragon from hiding to flying to going too far, describing how something develops from its start to its peak. "Nine" in a line name means a yang line; first, second and so on to top give its position from the bottom.
- First nine: "Hidden dragon. Do not act." The time is not ripe; build strength first.
- Second nine: "Dragon appearing in the field. It is favourable to see the great person." You start to be seen; seek someone who can guide you.
- Third nine: "The noble one is active all day and still wary at night. Danger, but no blame." Steady effort and alertness keep you from error.
- Fourth nine: "Perhaps leaping in the depths. No blame." You may try to rise or step back; reading the moment correctly is not a mistake.
- Fifth nine: "Flying dragon in the heavens. It is favourable to see the great person." The best position, where your strengths can work.
- Top nine: "Arrogant dragon will have regret." Going too high brings regret; at a peak, know when to hold back.
What is "using nines"?
Qian has one extra statement: "A flight of dragons without a head. Good fortune." Strength that does not push to be first works out well. Only Qian has this; Kun has a matching "using sixes".
Where does "heaven moves with strength" come from?
From Qian's Image commentary: heaven moves vigorously without rest, and the noble one likewise strengthens themselves without ceasing. It has become a widely quoted motto.
What can you learn from Qian?
The six lines make a good exercise in timing. Is your situation more like hiding, being newly seen, working hard, getting ready to leap, being in the right place, or having gone too far? Read this way, the hexagram is more useful than a verdict of good or bad luck.
FAQ
- Is Qian a good hexagram?
- Its judgment is broadly positive, but the top line warns that going too far brings regret. Every hexagram mixes favourable conditions with cautions, so good-or-bad is not a useful way to read it.
- What does "hidden dragon, do not act" mean?
- The dragon is still under water and the time is not ripe. Hold off, build your strength and wait for the right moment.
- Why is the fifth line special?
- The fifth line is traditionally the most honoured position in a hexagram. Qian's fifth line, the flying dragon, later gave Chinese a common phrase for the throne.
Practise with an app
To practise these ideas, YiJian is an iPhone course that teaches the I Ching from zero, with eight interactive beginner lessons (the first three free) and illustrated guides to all sixty-four hexagrams. Casting in the app is a practice feature for checking what you have learned and reflecting on your situation; it does not make decisions for you.