Core terms
Bull flag
A chart shape made of a fast rise (the pole) followed by a short, shallow drift sideways or down (the flag) that stays in the upper part of the pole. It describes bars that have already printed, not the next move.
Definitions vary between pattern books, and a loose definition lets a trader count the flags that worked and call the others "not real flags". One countable version, used in the Foundations course: a pole of at least 3 consecutive 1-minute bars with higher closes, rising at least 8%; a flag of 3 to 8 bars with no new high and no close below the pole's 50% retracement; flag volume below pole volume; a trigger at the first trade above the flag high. These thresholds are a choice, not a standard.
After the break, outcomes include a run to the target, a fast failure back through the flag, and sideways chop until a time stop. Lighter flag volume fits several explanations and does not show intent.
Bear flags and pennants
A bear flag is the mirror image: a fast drop, then a shallow drift up. A pennant is a flag whose highs and lows converge; count it under its own definition.
What traders should verify
Write the definition before counting, apply it to every flag in the sample, including the unclear ones, and record outcomes in R after costs. Keep the definition fixed for a whole practice block and change it only between blocks.
Do not conflate
Trader usage; there is no official definition. A published bull flag success rate without a definition, a sample size and costs cannot be checked, and a few points of difference in the hold rate can change the sign of expectancy.
Primary source
Trader usage: there is no official definition, and platforms and tools may calculate it differently.