Trendlines

Introduction

Support and resistance, as you have met them so far, are horizontal — floors and ceilings at roughly fixed prices, which describe a market moving sideways. But markets often are not sideways. They rise, and they fall. To describe support and resistance in a moving market, we tilt the line. That tilted line is a trendline, and it is the third building block of price action.

A trendline takes the same logic you already understand — buyers stepping in, sellers stepping in — and tracks it as it drifts up or down over time. Master it and you can describe not just where a market has reacted, but the direction and pace at which it is travelling.

What A Trendline Is

A trendline is a straight line drawn along a market's rising lows or falling highs, acting as sloping ("dynamic") support or resistance.

There are two kinds, and they are exact mirrors:

• An uptrend line is drawn underneath a series of rising lows. Because price keeps turning up from it, it acts as dynamic support — a floor that rises over time.
• A downtrend line is drawn above a series of falling highs. Because price keeps turning down from it, it acts as dynamic resistance — a ceiling that falls over time.

Notice the definition of a trend hiding inside this: an uptrend is a sequence of higher highs and higher lows; a downtrend is a sequence of lower highs and lower lows. The trendline simply traces the lows (or highs) of that sequence.

How To Draw One — And Confirm It

The mechanics are simple, but the discipline is everything.

Two points define a line; a third confirms it. Any two lows can be connected by a straight line — but two points might be pure coincidence. The line only becomes meaningful when price comes back a third time and respects it (turns away from it). Until that third touch, you have a hypothesis, not a confirmed trendline.

A few practical rules keep trendlines honest:

• Anchor to clear reactions, the obvious swing lows or highs — not to every minor wiggle.
• Allow a zone. Just like horizontal support, a trendline is really a narrow band; a small overshoot is not automatically a break.
• Prefer closes. A trendline is considered broken when price closes through it, not when a single wick pierces it.
• Don't force it. If you have to ignore several clear lows to make a line "work," the line is wrong.

Slope: What The Steepness Tells You

Because trendlines have an angle, the angle itself carries information.

• A shallow, steady slope reflects an orderly, sustainable pace — the kind of advance or decline that can persist for a long time.
• A very steep slope reflects a rapid pace that is hard to maintain. Steep trends frequently break their line and then either pause or settle into a gentler slope. (A break of a steep line is not, by itself, a forecast of reversal — often it just means the trend is slowing to something more sustainable.)

Analysts sometimes redraw a trendline to a shallower angle after a steep one breaks — the trend continues, just at a calmer pace. The slope is a description of tempo, and tempo changes.

Channels

If a market is travelling in a trend, its swings on the other side are often roughly parallel to the trendline. Draw a second line parallel to the first, touching those swings, and you have a channel — price travelling between sloping support and sloping resistance.

Channels are a tidy way to describe a trending market, but the same humility applies: price is not contractually bound to bounce between the lines. The channel is a frame for what has happened and a guide to what to watch, not a promise.

A Worked Example

Suppose a share bottoms at 40, climbs to 55, pulls back to 46, climbs to 62, pulls back to 52, and climbs on. The lows — 40, 46, 52 — are rising. Connect them and you have an uptrend line: dynamic support climbing from the low 40s. Each pullback that holds the line confirms the structure (higher highs, higher lows).

This lets you describe the market precisely — "an orderly uptrend, lows respecting a shallow rising line" — and identify what would change that description: a decisive close below the line, which would signal the rising lows have, for now, stopped rising. What happens after such a break is the subject of the next article, breakouts. Note what the trendline does not do: it does not promise the next low will hold, and it is not a reason to act on its own.

The Discipline Trap

Trendlines are drawn by hand, which makes them powerful and dangerous in equal measure. The danger is confirmation bias: it is remarkably easy to draw the line you wish were there — tilting it, ignoring an inconvenient low, or cherry-picking start points — until a "trend" appears that the broader evidence does not support.

Guard against it with a simple test: would someone else, shown the same chart, draw roughly the same line? If your trendline depends on ignoring obvious reactions or on a clever choice of anchor only you can see, it is not describing the market — it is describing your hope. A well-drawn trendline should be almost obvious.

Used with that discipline, trendlines turn the static idea of support and resistance into a moving picture of direction and pace — and set up the single most important event in price action: what happens when a level finally gives way.