Chart pattern · Continuation · Bullish
What is it, in one line
A sharp advance, the flagpole, followed by a brief, shallow, downward-drifting consolidation.
Bullish · Continuation · verdict: Traditional claim, not yet measured here
A sharp advance, the flagpole, followed by a brief, shallow, downward-drifting consolidation.
Method
Conventional target: A break above the flag projects a rise equal to the flagpole’s length.
Invalidated by: A retracement back to the flagpole’s start invalidates the pattern.
A pole — the prior advance measured by trendSlope — followed by a consolidation whose swing highs and swing lows are both drifting DOWN, and whose depth is small against the pole.
The traditional claim
Read as a bullish continuation, resolving upward out of the drift.
How this detection is wrong
The pole requirement is what makes this a flag rather than a downtrend. The drift must also stay shallow: a deep pullback is a reversal, not a flag.
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 |
|---|---|---|
| pivotLeft | bars to the left of a swing | 3 |
| pivotRight | bars to the right before a swing is confirmed | 3 |
| lookback | bars searched for the swings | 120 |
| atrPeriod | bars of ATR used to size everything below | 14 |
| flatTol | how level two points must be | 0.02 |
| minSepAtr | separation required between swings, in ATR | 1 |
| poleBars | bars the pole may take to form | 20 |
| minPoleSlope | pole slope required | 2 |
| maxFlagAtr | flag drift permitted, in ATR | 6 |
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.
A pole — the prior advance measured by trendSlope — followed by a consolidation whose swing highs and swing lows are both drifting DOWN, and whose depth is small against the pole. The detector also requires a prior uptrend, so the same shape in the wrong context is not counted.
It is read as bullish. Read as a bullish continuation, resolving upward out of the drift.
The pole requirement is what makes this a flag rather than a downtrend. The drift must also stay shallow: a deep pullback is a reversal, not a flag.
As an executable rule over open, high, low and close, with 9 named parameters — including bars to the left of a swing 3, bars to the right before a swing is confirmed 3, bars searched for the swings 120 — 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 uptrend, its mirror a preceding downtrend.
Bear Flag: A sharp decline followed by a shallow drifting rally.