The London breakout is probably the most searched forex strategy on the internet, and also one of the most oversold: countless pages promise a mechanical system with a specific win rate, backed by a backtest that conveniently starts on a good month. Strip away the marketing and there is a real, testable idea underneath: mark the Asia session's range, and trade whichever side London breaks first, since London typically supplies the day's real directional volume after Asia's quiet consolidation.
That core idea is sound. The specific numbers attached to it in most articles, 80 percent win rates, three trades a week that never lose, are not. A version worth trading needs realistic expectations and two or three filters most of the popular writeups skip entirely.
The classic rules
Mark the Asia session's high and low, roughly 7pm to 3am New York time, before London opens. Place a buy stop a few pips above the range high and a sell stop a few pips below the range low, so whichever direction breaks first triggers automatically, and cancel the opposite order once one triggers. The stop for the triggered trade sits on the far side of the Asia range, since a genuine breakout should not immediately retrace back through the entire box it just escaped. The target is typically a measured move, the Asia range's own height projected from the breakout point.
The honest statistics
Hand tested across ordinary weeks rather than a cherry picked sample, this setup wins somewhere in the neighborhood of 40 to 50 percent of the time on EURUSD and GBPUSD, not the inflated figures common in strategy marketing. What makes it profitable, when it is, is reward to risk: a clean breakout that runs the full measured move often pays two to three times the risk, so a strategy that wins under half its trades can still be net positive over a large sample. The honest failure mode is the Asia range being too narrow, produced by a genuinely quiet night, in which case London's first move often breaks it, fails, and reverses through the other side entirely, stopping out the breakout trader on the wrong side.
Filters that separate signal from folklore
A minimum range width filter helps enormously: on EURUSD, an Asia range under 15 pips is usually too thin to trust, since almost any London move breaks it regardless of real direction. A day of week filter matters too, with Friday's typically thinner, choppier action producing a noticeably worse hit rate than Tuesday through Thursday. A news filter belongs here as well: skip the setup entirely if a high impact release lands in the first hour of London, since the breakout in that case reflects the headline rather than the range.
A worked GBPUSD breakout
GBPUSD's Asia range runs from 1.2640 to 1.2668, a 28 pip range, comfortably above the minimum width filter, on a Wednesday with no major UK or US data before 9am London time. A sell stop sits at 1.2637, three pips below the range low. Price triggers the short at 1.2637. The stop goes at 1.2672, four pips above the range high, a 35 pip risk. The target is the range's own 28 pips projected downward from the breakout point, near 1.2609, for a 0.8 to 1 reward to risk on this particular range, which is on the low side and part of why the filters above matter so much to which setups actually get taken.