I Ching hexagram 21
Hexagram 21: Shi He
Biting Through · 火雷噬嗑 · Fire above, Thunder below
An obstacle sits between two sides and has to be bitten through with clear rules and firm, fair action.
What this hexagram is about
Something blocks agreement, such as a broken promise, and it will not clear on its own. Shi He (Biting Through) looks like a mouth with something lodged between the teeth, and the lines run from easy cases to hard ones.
A way to think about it
Name the one thing blocking agreement or progress in your situation, as exactly as you can. Then ask what fair, firm handling of it would look like.
The text, with Legge's translation
Judgment
亨。利用獄。
Shih Ho indicates successful progress (in the condition of things which it supposes). It will be advantageous to use legal constraints.
Things go through once the obstruction between the jaws is bitten through. The judgment says this is a time for resolving a case firmly and fairly, as a court does.
Image
雷電，噬嗑；先王以明罰敕法。
(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.
Line 1 · 初九
屨校滅趾，无咎。
The first line, undivided, shows one with his feet in the stocks and deprived of his toes. There will be no error.
A small penalty early on, like stocks on the feet, stops a person before the wrongdoing grows, and acting this early draws no fault.
Line 2 · 六二
噬膚滅鼻，无咎。
The second line, divided, shows one biting through the soft flesh, and (going on to) bite off the nose. There will be no error.
The case is as easy as biting soft meat, so you bite in deep, even past the nose. The force is excusable because the matter was clear.
Line 3 · 六三
噬昔肉，遇毒；小吝，无咎。
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.
An old, stale case is hard to bite into, and you get a bad taste from it, meaning resentment from the people involved. You are left with a small regret and no real fault.
Line 4 · 九四
噬乾胏，得金矢，利艱貞，吉。
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.
A tough case, like gristly meat on the bone, yields metal arrows, which stand for strength and a straight aim. Staying steady through the difficulty is what carries it.
Line 5 · 六五
噬乾肉，得黃金，貞厲，无咎。
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.
Hard dried meat turns up yellow gold, fairness joined with firmness. Stay aware of the danger in handling the case and nothing counts against you.
Line 6 · 上九
何校滅耳，凶。
The sixth line, undivided, shows one wearing the cangue, and deprived of his ears. There will be evil.
The person wears a heavy wooden collar that covers the ears, someone who piled up wrongs and refused to listen, and it ends badly.
Chinese text: the received Zhouyi, public domain. English: James Legge, The Yi King, Sacred Books of the East vol. 16 (1882), public domain. Plain notes written by this site.
Questions
I cast hexagram 21. Which text do I read?
With no changing lines, read the judgment: "Shih Ho indicates successful progress (in the condition of things which it supposes). It will be advantageous to use legal constraints." With changing lines, read the lines that changed. When several change at once, Zhu Xi's rules decide which text leads, and the casting page marks it for you.
What are the nuclear, opposite and inverted hexagrams of Shi He?
The nuclear hexagram is 39. Jian (Obstruction). The opposite is 48. Jing (The Well). The inverted hexagram is 22. Bi (Adornment).