Upper trigram
☲
Fire (Li) above
Clarity and attachment.
FamilyMiddle daughter
ElementFire
Hexagram 21 of 64
I Ching hexagram 21 ☲☳ Biting Through
I Ching hexagram 21, Biting Through, is fire above, thunder below. In brief: decisive action against an obstruction. Counting from the bottom, its solid lines sit in places 1, 4 and 6 and its broken lines in 2, 3 and 5.
- Lines, bottom up
- ⚊⚋⚋⚊⚋⚊ 100101 · 1 = solid
- Trigrams
- Fire over Thunder Li ☲ / Zhen ☳
- Every line changed
- № 48 The Well
- In Legge, 1882
- p. 102 Sacred Books of the East, vol. 16
Legge, The Yî King, 1882.
Lower trigram
☳
Thunder (Zhen) below
Arousal and shock.
FamilyEldest son
ElementWood
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What the text says, in plain terms
The Judgement and the Image of hexagram 21
The Judgement
Biting through an obstacle. Something is blocking unity, and it has to be dealt with decisively; clear, fair judgment and consequences resolve it.
The Image
Thunder and lightning together. The lesson is to make the rules clear and apply them firmly, so that justice is visible and understood.
A summary of meaning written for this site, not a translation — James Legge’s 1882 translation of the full text follows below. How the Judgement and the Image are read, and which translations to use →
Primary source
Hexagram 21 in James Legge’s translation
“Shih Ho indicates successful progress (in the condition of things which it supposes). It will be advantageous to use legal constraints.”
“(The trigrams representing) thunder and lightning form Shih Ho. The ancient kings, in accordance with this, framed their penalties with intelligence, and promulgated their laws.”
The lines
- Line 1 · bottom The first line, undivided, shows one with his feet in the stocks and deprived of his toes. There will be no error.
- Line 2 The second line, divided, shows one biting through the soft flesh, and (going on to) bite off the nose. There will be no error.
- Line 3 The third line, divided, shows one gnawing dried flesh, and meeting with what is disagreeable. There will be occasion for some small regret, but no (great) error.
- Line 4 The fourth line, undivided, shows one gnawing the flesh dried on the bone, and getting the pledges of money and arrows. It will be advantageous to him to realise the difficulty of his task and be firm,—in which case there will be good fortune.
- Line 5 The fifth line, divided, shows one gnawing at dried flesh, and finding the yellow gold. Let him be firm and correct, realising the peril (of his position). There will be no error.
- Line 6 · top The sixth line, undivided, shows one wearing the cangue, and deprived of his ears. There will be evil.
James Legge, trans., The Yî King, The Sacred Books of the East, vol. 16 (Oxford: Clarendon Press, 1882), p. 102 — read the original text.
Words in parentheses are Legge’s own: in his preface he explains that they supply what the original writer left unsaid. “Undivided” and “divided” are his terms for yang and yin lines, counted from the bottom. The Image comes from the second appendix of the book, the Treatise on the Symbolism.
Biting Through for a decision
Confront the obstacle directly instead of working around it. Be firm and fair; half-measures leave the blockage in place.
I Ching 21 in love and relationships
Something unspoken — a lie, a grievance, an interference — is getting between people. It needs to be addressed openly.
Hexagram 21 at work
Enforcing standards, resolving disputes and removing a bottleneck. Decisive action now saves a long drag later.
The six lines of hexagram 21
Read from the bottom up. This figure runs yang yin yin yang yin yang — what each position means.
3 yang and 3 yin lines. Two of the six stand in their proper place, and the pair 3–6 answers.
What the two trigrams do to each other
Inner and outer
Thunder below — arousal and shock — is the private, inner side of hexagram 21.
Fire above — clarity and attachment — is the world that side meets.
The five-element relation
Wood below generates Fire above in the five-element cycle: the lower trigram feeds the upper. Energy moves upward and outward, which is the more productive of the two directions.
Read as a family
The middle daughter sits above and the eldest son below. A brother and a sister, the younger one on top — siblings rather than parent and child, with the junior one taking the lead.
Calculated from the lines
Hexagrams connected to hexagram 21
Nuclear hexagram
39 · Obstruction
What is happening beneath the surface.
Lines 2–4 give Gen (Mountain) as the lower trigram, lines 3–5 give Kan (Water) as the upper.
Opposite hexagram
48 · The Well
The situation turned inside out.
Change all six lines and Fire over Thunder becomes Water over Wind.
Inverse hexagram
22 · Grace
The situation seen from the other side.
Turn the figure upside down and Fire over Thunder becomes Mountain over Fire.
None of these are assigned by an author — each follows from the arrangement of lines.
The image
Fire above, Thunder below.
Fire over Thunder: clarity and attachment meeting arousal and shock.
Sources
Statements of fact on this page were checked against these sources in October 2026. How we choose and check sources: editorial policy.
Cite this page
AstroHot. “I Ching Hexagram 21: Biting Through.” Accessed October 27, 2026. https://astrohot.com/i-ching/hexagram/21/
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