# Key Reversal A Chart & Candlestick Patterns concept (Reversal chart patterns) in the LuxAlgo Library, with 1 indicator implementation. ## What is a Key Reversal? A key reversal is a single-bar failure at a trend extreme. In the bearish form, price pushes (often gaps) to a new high above the prior bar's high, then sells off to close below the prior bar's close, or below the prior bar's low in strict definitions. The bullish mirror makes a new low and closes back above. It is the 'one-day reversal' of classic charting literature: the market accepts new extremes intraday and rejects them by the close, leaving everyone who chased the push underwater. The pattern is tape-reading vintage. One-day reversals were catalogued in the earliest bar-chart literature and carried into the standard references, and the association with climactic single-session turns runs back to the Livermore era of reading reversals off the tape. The name reflects the old claim attached to it: that such bars can mark the key turning point of a move, a claim modern usage has learned to soften considerably. The strict form (a new extreme plus a close beyond the prior bar's opposite side) is also an [outside bar](https://www.luxalgo.com/library/concept/outside-bar/), and the logic overlaps with a [swing failure pattern](https://www.luxalgo.com/library/concept/swing-failure-pattern/): a probe beyond a reference extreme that closes back through it. Classic descriptions add climactic volume as a qualifier. Single bars fail routinely, so the pattern reads best as a warning at an extreme rather than proof of a turn. Definition strictness is the practical variable. Loose versions ask only for a new extreme and a close below the prior close; strict versions demand the close beyond the prior bar's opposite extreme, heavy volume, and a mature trend behind it, and each added requirement trades frequency for quality. Timeframe scales the meaning the same way: daily key reversals are common furniture, while weekly and monthly versions are rare enough that chartists track them as candidates for durable swing extremes. ## How to identify a key reversal on a chart The bearish case at a high is described; mirror every step at lows. 1. Require an extended advance into the bar: without a trend to exhaust, the geometry is just an ordinary volatile bar. 2. Look for the push: the bar trades above the prior bar's high, ideally gapping up or accelerating, the last buyers committing at the top. 3. Demand the failure: the same bar closes below the prior bar's close, or below the prior bar's low under strict definitions. 4. Check the volume: classic treatments want climactic activity, maximum effort at the extreme producing no held progress. 5. Trigger on follow-through, not the bar itself: a break of the key reversal bar's low is the conventional entry, with the stop above the new high it printed. 6. Void the read on a fresh extreme: a close above the reversal bar's high resolves the failure as continuation. ## How traders use it - As an exhaustion alert in an extended trend: a key reversal after a sustained run is a common cue to take partial profits or tighten a trailing stop, ahead of any actual reversal entry. - As a fade trigger with confirmation: entry on a break of the key reversal bar's opposite extreme, stop beyond the new high or low it printed, accepting that many such bars only pause the trend. - On higher timeframes: weekly and monthly key reversals are watched as candidates for durable swing highs and lows, particularly when they print on a [volume spike](https://www.luxalgo.com/library/concept/volume-spike/). - As a scanning condition: the geometry (new extreme, close beyond the prior bar's close or low) codes directly into screeners, usually filtered further by trend length, range size against a [wide-range bar](https://www.luxalgo.com/library/concept/wide-range-bar/) standard, and relative volume. - As candlestick crosswalk: the same event often qualifies as a bearish [engulfing bar](https://www.luxalgo.com/library/concept/engulfing-bar/) at a high, and its two-bar cousin distributes the identical trap across a [two-bar reversal](https://www.luxalgo.com/library/concept/two-bar-reversal/), so scanners frequently flag one turn under several names. ## Key Reversal vs neighboring reversal bars - **Outside Bar** (https://www.luxalgo.com/library/concept/outside-bar/): An outside bar only requires engulfing the prior bar's range, anywhere on the chart. The key reversal adds the context that gives the geometry meaning: a trend to exhaust, a push to a new extreme first, and the close-back-through as the failure. - **Two-bar Reversal** (https://www.luxalgo.com/library/concept/two-bar-reversal/): The two-bar reversal spreads the same trap across two committed candles: strength one way, then strength the other. The key reversal compresses the whole round trip into a single bar, which makes it rarer and, on higher timeframes, heavier. - **Pin Bar** (https://www.luxalgo.com/library/concept/pin-bar/): A pin bar rejects an extreme with a long wick and a small body, hesitation crystallized. The key reversal is a full traverse: acceptance of new prices intraday, then a close beyond the prior bar's level, so it records commitment failing rather than merely a probe rejected. ## FAQ ### What is the difference between a key reversal and an outside bar? An outside bar only requires engulfing the prior bar's range. A key reversal requires trend context and sequence: a push to a new extreme of the move first, then a close back beyond the prior bar's close or low. Strict key reversals are therefore a subset of outside bars, while a random outside bar mid-range carries none of the same exhaustion logic. ### Does a key reversal need high volume to count? Most classic definitions emphasize unusually heavy volume, because the pattern is meant to capture a climax: maximum effort at the extreme producing no held progress. Bar geometry alone still qualifies under looser definitions, but a key reversal on quiet volume is weaker evidence, and many traders skip those or demand follow-through on the next bar. ### Is a key reversal the same as a bearish engulfing pattern? They overlap heavily at highs. A bearish engulfing candle whose high also exceeded the prior extreme and whose close undercut the prior bar's body will usually satisfy loose key-reversal definitions too. The vocabularies differ in emphasis: engulfing is a candlestick shape defined on bodies, while the key reversal is a bar-chart event defined on extremes, closes, and trend position. ### Does the bar need to gap to a new extreme? The classic commodity-era description featured the gap, morning enthusiasm buying the open above yesterday's high, because daily futures charts of that period gapped routinely. Modern definitions mostly require only the push to a new extreme, gap or not, since around-the-clock markets rarely gap intraday. Where opening gaps still exist, a gap-and-fail version reads as the stronger trap. ### Are weekly and monthly key reversals more reliable? They are rarer and represent far more participation, a whole week or month of trade accepting new extremes and rejecting them by the close, so chartists weight them more heavily as candidates for lasting swing points. More weight is not certainty: higher-timeframe key reversals still fail, and the practical treatment stays the same, a warning that demands follow-through before it is a position. ### How do traders typically trade a key reversal? Conservatively, in two stages. The bar itself triggers defense: profits trimmed, stops tightened on positions riding the prior trend. The offensive trade waits for confirmation, conventionally a break of the reversal bar's opposite extreme, with the stop beyond the new high or low the bar printed. The pattern's known failure mode is the strong trend that absorbs the scare and continues, which the confirmation step exists to filter. ## Implementations in the Library - N Bar Reversal Detector (LuxAlgo): https://www.luxalgo.com/library/indicator/n-bar-reversal-detector/ ## Related concepts - Head & Shoulders: https://www.luxalgo.com/library/concept/head-and-shoulders/ - Inverse Head & Shoulders: https://www.luxalgo.com/library/concept/inverse-head-and-shoulders/ - Double Top/bottom: https://www.luxalgo.com/library/concept/double-top-bottom/ - Rounding Top/bottom: https://www.luxalgo.com/library/concept/rounding-top-bottom/ - V-top/V-bottom: https://www.luxalgo.com/library/concept/v-top-v-bottom/ - Diamond Top/bottom: https://www.luxalgo.com/library/concept/diamond-top-bottom/ - Island Reversal: https://www.luxalgo.com/library/concept/island-reversal/ - Wolfe Waves: https://www.luxalgo.com/library/concept/wolfe-waves/ - Bart Pattern: https://www.luxalgo.com/library/concept/bart-pattern/ - Rare Reversal Patterns: https://www.luxalgo.com/library/concept/rare-reversal-patterns/ --- Source: https://www.luxalgo.com/library/concept/key-reversal/ (LuxAlgo Library, the encyclopedia of trading & technical analysis). Free to use with attribution: https://www.luxalgo.com/library/license/