What it is. A brief defensive window you open on a button, timed to the instant an attack lands. Hit it and the exchange flips: the attacker is staggered and you get a free, oversized riposte. Miss it and you eat the hit — often worse than if you’d never tried.

Player fantasy / why it’s fun. Reading the killing blow and answering it. The parry is the moment defense becomes offense in a single frame — you didn’t survive the attack, you invited it. Mastery reads as calm: the better player looks like they’re doing less.

The verb

Watch the tell → press parry so your window overlaps the moment of impact → on success, the attacker recoils into a punishable state and you land a riposte. It is not “hold to be safe” (that’s mechanic-block); it is a committed spike of safety you place on a read.

How it feels / why it’s fun

• The read, not the reflex. A fair parry is answered by anticipation more than twitch — you commit before certainty. That is the whole pattern-risk-reward engine of the mechanic. See system-counter-systems.
• Legibility is the contract. A parry is only fair if the tell is. The window is a promise the enemy’s wind-up must honor. Design the wind-up before the window; that’s system-telegraphs and pattern-readability.
• Asymmetric payout. Success should feel enormous and failure should sting — the gap is where the tension lives. A parry that’s merely “block, but slightly better” has no pull. Cf. antipattern-false-depth.
• The frozen beat. On success, the whole world catches for a few frames — the clang, the hitstop, the flash. That contrast is the reward’s flavor; choreograph it per pattern-juice-choreography.

Tuning levers

Two archetypes fall out of this table:

• Deflect-parry — tight window, low whiff cost, tuned so the rhythm of an exchange is the fight; you can be aggressive because failure is survivable. That’s mechanic-deflect (Sekiro).
• Commit-parry — generous but scary; a big riposte gated behind a real punish-on-whiff. The parry is a rare, decisive read, not a beat you hold (Dark Souls, Street Fighter’s parry lineage).

Decide which one you’re building and tune the whiff cost and window as a matched pair — a tight window with a brutal whiff is masochism; a wide window with no penalty is a free button.

Slots into

• Genres: genre-soulslike and genre-action-adventure (the signature read in system-combat-model), genre-fighting-game (the mind-game layer), genre-rhythm and genre-precision-platformer (parry-as-beat), even genre-tactics where a parry is a predicted interrupt.
• Anchors: anchor-dark-souls (commit-parry into a critical), anchor-street-fighter (the parry as spacing mind-game), anchor-cuphead (the pink-parry as a rhythmic reset), anchor-into-the-breach (reads-as-parry: you counter the telegraphed attack a turn ahead — the same fantasy in a turn-based skin).
• Pairs with mechanic-block (the safe floor a parry is the spike above), mechanic-dodge-roll (the escape alternative — offer both, let the player choose their answer), mechanic-lock-on (parries want a committed target), mechanic-charge-attack as the riposte payload.
• Systems: system-boss-design leans on it for pattern-pacing-and-tension; system-enemy-archetypes must earn parryability with a clean wind-up.

Twist seams

• Parry but a perfect one rewinds the exchange one beat (mechanic-swap) — a frame-perfect parry doesn’t just block, it un-happens the attack: both fighters snap back to the position they held one beat prior, and the enemy’s move is spent. The fantasy shifts from “counter” to “veto.” Now the read is layered — do you parry to punish, or parry to erase and reset spacing? Kin to mechanic-rewind; verify the state snapshot is deterministic.
• Parry but you can only parry the color you currently are (constraint) — you carry a color; attacks carry a color; a parry only lands when they match, and you swap your color on a separate input (Ikaruga’s polarity, made defensive). The window is no longer the only variable — are you the right state is. This forces color-management under pressure and turns an incoming barrage into a legible pattern-read. See system-status-effects.
• Parry but success is a shared resource you spend to interrupt (resource-swap) — parries don’t punish directly; they fill a counter meter you bank and later spend to cancel an enemy’s unblockable. Defense becomes a savings account, and the tension is when to cash it. Frames the read as economy — system-resource-loops.

How it wires to Hayao

• Model the window as explicit sim state: a small integer counter of remaining active frames, opened on the input tick and decremented each fixed step. Hit resolution checks “is a parry window active at the moment of impact?” — pure, ordered, deterministic. It belongs in hashed state.
• Tie the window to the enemy’s attack timeline, which is also sim state — the tell, the active frame, the recovery. The parry is fair because both clocks advance on the same fixed timestep and a replay reproduces the exact overlap. Study an isolated timing/telegraph lab under sandboxes/ before wiring a full encounter.
• The clang, the flash, the hitstop, the slow-mo on success are pure view — tag those nodes cosmetic so they stay out of world.hash(). Design the feel here; prove the readability of the tell and the punch of the riposte in design/JUICE.md, and prove the encounter is winnable-by-read in design/FUN.md.
• If parries build posture toward an execution, that meter is sim state too; the bar you draw is cosmetic, the number it reflects is not.

Fails when…

• The tell is unreadable. No legible wind-up → the parry is a coin flip, and a coin flip you get punished for is antipattern-guess-the-designer. The window is only as fair as the telegraph.
• Whiff has no cost. Parry becomes the always-on optimal answer; blocking and dodging die. Give it a real recovery you can be punished in, or you’ve built antipattern-boring-optimal.
• The reward is stingy. A riposte that barely out-damages a normal hit means nobody takes the risk — the mechanic is decoration. That’s antipattern-false-depth.
• Coverage is a lie. If some attacks are unparryable but look identical to parryable ones, you’ve turned a read into a memory-test. Unparryable attacks need a different tell (color, sound, animation) — a fair “don’t parry this” signal.
• The window scales with framerate. Count active frames on the fixed step, not real time — a framerate-dependent window breaks muscle memory and determinism both. Cf. antipattern-input-lie.
• Every enemy is parry-bait. If parrying trivializes all combat, you’ve deleted the reason to ever mechanic-dodge-roll or mechanic-block. Mix in un-parryable pressure (grabs, delayed swings, multi-hits) so the read stays a choice.

See also

• mechanic-deflect — the tight, rhythmic sibling; when the exchange tempo is the fight, build that.
• mechanic-block — the safe floor the parry is the risky spike above; ship them together.
• mechanic-dodge-roll — the escape answer; offering both parry and dodge is what makes a defensive read a decision.
• system-telegraphs & pattern-readability — the tell is the mechanic; design it first.
• system-counter-systems & pattern-risk-reward — the payout math that makes the read worth committing.
• system-boss-design — where a well-tuned parry becomes the shape of a whole fight.