A trendline is the simplest structural tool on a chart — a diagonal line drawn through successive higher lows (in an uptrend) or lower highs (in a downtrend). For as long as price respects that line, the trend is intact. When price decisively breaks through it, something has changed.
The trendline break is one of the oldest signals in technical analysis, and it underpins half the other patterns on this page — triangles, wedges, channels and flags are all defined by trendlines. Understanding how trendlines behave (and how they fail) is foundational for every other structural read.
A valid trendline has at least three touches. Two points draw a line, but any two random points draw a line — the third touch is what confirms the market is actually using the level. Four or more touches is even better. The slope tells you the strength of the trend: a steep line is fragile, a shallow line is sustainable.
Draw through the wicks for the most honest line; some traders draw through the bodies for a cleaner signal. Both have proponents — pick one rule and stay consistent. Constantly redrawing the line to fit recent price is curve-fitting, not analysis.
On large multi-year charts, prefer a log scale. Percentage moves are what matter, not absolute price moves, and a linear chart compresses the early part of a long trend into uselessness.
A wick poking through a trendline is not a break. A single bar’s tail touching the line is just noise. The signal is a close on the other side — and ideally a decisive close, with a body that fills most of the candle’s range.
Stricter traders add a second filter: the close must be beyond the line by some buffer (often 0.25-0.5% of price, or some multiple of ATR). This filters out marginal closes that barely clip through. Whichever rule you use, define it before the trade, not after.
The simplest version: price closes decisively through the trendline and continues without looking back. No retest, no second chance — if you didn’t enter on the breaking candle’s close, you missed it.
This is the version most people imagine, and the least common in practice. Strong break-and-go moves often happen on news, sudden flows, or at the end of long compressions where pressure has been building. They reward conviction and punish hesitation.
The trade-off: entering on a break-and-go means you don’t get confirmation. The breaking candle could be a stop hunt that reverses. Position size should reflect the higher uncertainty. A small starter position you can add to is often better than a full-size bet on the break alone.
The cleanest setup. Price breaks the trendline, sells off (or rallies, in a downtrend break), then pulls back to test the underside of the broken line — what was support is now resistance. If the line holds on the retest, the move continues; if price closes back through it, the break was false and the original trend is intact.
Most professional traders prefer this version. The retest gives you confirmation, a tight reference for your stop, and a much better risk:reward than chasing the break itself.
Look for a clear rejection candle at the retest — a long wick into the underside of the line with a body that closes well away from it. A weak retest where price grinds along the line for many bars is a sign the broken trendline is being absorbed and the break may fail.
Trendline breaks fail. Often. The three most common ways:
A bar’s wick punches through the line but the body closes back inside the trend. No close-through means no break. The trendline holds and price continues in the original direction.
The breaking candle has a marginal body that just clips beyond the line. A close like this is often retested immediately and absorbed back into the trend. Wait for a buffer or for the retest to confirm.
Trader redraws the line to be steeper after a single touch, then takes the “break” of a line that wasn’t really there. This is overfitting masquerading as signal.
The pattern that catches most retail traders: a sharp break, a fast pullback that looks like a retest, then a continuation move beyond the original break. Half the time this is real; the other half it is a liquidity sweep designed to trigger break-traders’ stops before the trend resumes. The defence is patience — one rejection candle, not three minutes of action, decides whether the retest is holding.
A trendline break in isolation is a coin flip with a story. A trendline break that lines up with other signals is where the edge lives:
• A break that also breaks a horizontal support / resistance level is far stronger than a break of the diagonal alone.
• A break that aligns with a BoS or CHoCH on the higher timeframe confirms the regime change rather than just the line break.
• A retest that lands inside a Fair Value Gap or Order Block doubles up the rejection logic — two methodologies agreeing on the same level.
• A break that sweeps recent highs / lows first (a liquidity sweep) is often a stronger reversal signal than a clean break alone, because the stops have already been taken.
One signal is a probability. Three signals at the same level is an edge.
Key insight: Trendlines are subjective. Ten traders draw ten slightly different lines. The market doesn’t care which one you drew — it cares about levels where significant flow defends the price. A trendline that has held four times on heavy volume is a real level; one that you tilted yesterday to fit the chart isn’t. Draw lines you would have drawn last week and yesterday and a month ago. If you keep redrawing, you are not analysing — you are storytelling.
Trendlines work in trending markets and fail in chop. Of any 100 trendlines you draw across a chart’s history, most will break unceremoniously, some will hold for months, and a few will define multi-year regimes. There is no way to know in advance which is which.
The discipline that makes trendline breaks useful is the same discipline that makes anything in trading useful: a rule defined in advance, a stop you respect, a target set before the trade, and the acceptance that any single trade is one observation in a long distribution. Most trendline breaks will not be the great trade of your career. A few will. Trade the system, not any individual instance of it.