Candlestick formation · Bullish
What is it, in one line
Opens below the prior low, then closes above the prior midpoint.
Bullish · 2 candles · verdict: rule and thresholds below
Opens below the prior low, then closes above the prior midpoint. The engine checks the formation as an executable condition over open, high, low and close, with a trend filter applied before the count is kept.
Method
Two candles. The first is a long down candle. The second opens below the first candle’s low and closes back above the midpoint of the first body — but not above its open, which is what separates it from a bullish engulfing.
The traditional claim
Traditionally read as a bullish reversal, weaker than an engulfing because the recovery is partial rather than complete.
How this detection is wrong
If the second candle closes above the first candle’s open it is an engulfing, not a piercing line. The two are mutually exclusive by definition, and penetration is the parameter that sets the boundary.
Published so the count can be reproduced. Every figure below is a parameter of the rule, not a preference: change one and the occurrence count changes with it.
| Parameter | Meaning | Default |
|---|---|---|
| trendPeriod | bars of prior trend inspected | 5 |
| maxPriorSlope | prior slope must be below | -1 |
| minPriorBodyAtr | the preceding body, at least, in ATR | 0.5 |
| penetration | how far the close must push into the previous body | 0.5 |
| atrPeriod | bars of ATR used to size everything below | 14 |
These share enough geometry that a detector can return more than one of them on the same bar. The engine reports every match rather than picking a winner.
Every pair on the site that can be mistaken for another, and what separates each: the look-alikes index.
Two candles. The first is a long down candle. The second opens below the first candle’s low and closes back above the midpoint of the first body — but not above its open, which is what separates it from a bullish engulfing. The detector also requires a prior downtrend, so the same shape in the wrong context is not counted.
It is read as bullish. Traditionally read as a bullish reversal, weaker than an engulfing because the recovery is partial rather than complete.
If the second candle closes above the first candle’s open it is an engulfing, not a piercing line. The two are mutually exclusive by definition, and penetration is the parameter that sets the boundary.
As an executable rule over open, high, low and close, with 5 named parameters — including bars of prior trend inspected 5, prior slope must be below -1, the preceding body, at least, in ATR 0.5 — all published on this page so the count can be reproduced. Strict and loose variants are defined as well, so the sensitivity of the count to those thresholds is visible rather than assumed.
Measurement pending re-run
No hit rate is published here yet. The run that would supply one was computed on engine ca6d9e36c81c; the engine is now cfb08765de7c. Its candlestick rows included the still-forming bar, and it predates the chart formations entirely, so those figures have been withdrawn rather than published with a caveat. The definition above is unaffected: it is what the detector tests, and no re-run changes it.
Same shape, opposite reading
The shapes are close, and the prior trend is what decides which one fired: this rule requires a preceding downtrend, its mirror a preceding uptrend.
Dark Cloud Cover: A long up candle, then a down candle opening above its high and closing back through its middle.