Hexagram 21, Biting Through, pictures jaws that cannot close because something is stuck between them. Learn why decisive, fair action is the only way past this obstacle.
Shi He combines fire (lightning) above and thunder below — clarity paired with decisive force. The hexagram's very shape is a mouth: the bottom and top lines are the jaws, and the firm line in the fourth place is the hard object stuck between them. The jaws cannot close until it is bitten through. That is the whole teaching: an unremoved obstacle keeps things from ever coming together. The commentary extends this to justice: penalties should be like thunder and lightning — swift, clear, and fair.
Drawing this hexagram means something concrete is lodged in the middle of your matter: an obstructive person, a deadlocked dispute, an issue that must finally be confronted. Avoidance only guarantees the two sides never close. The counsel is unambiguous — bite through: address it head-on and cut the knot. But do it the way thunder and lightning work together: investigate clearly first (the lightning), then act with authority and fairness (the thunder), so the outcome commands respect. The lines note that obstacles range from tender meat to dried gristle with bone — the harder the problem, the more preparation and tooling it needs, and sometimes the bite yields unexpected treasure.
In love, if something sits wedged in the relationship — an ambiguous third party, family tension, a resentment never voiced — name it and deal with it now; short pain beats long pain, and keep the conversation on the issue rather than widening the war. In career, it favors clearing backlogged disputes: unblocking the stalled project, letting go of the rule-breaker, finishing the contract fight properly — with rewards and penalties made public and fair. Financially, be decisive about collecting debts and settling contested accounts, and cut losing positions cleanly rather than letting one splinter jam your whole portfolio.
Shi He says: some problems do not dissolve on their own — they sit there until you bite through them. Decisiveness is not cruelty; what makes thunder and lightning worthy of respect is that they are swift and just. See clearly, bite through, let the jaws close — then move on.