Trend Lines & Channels

Overview

A trend line is a single straight line connecting lows (or highs). It is so simple it gets dismissed — yet it is the most direct way to visualise Dow Theory's "higher highs / higher lows".

It is also the easiest tool to draw arbitrarily. Depending on which points you connect, you can draw entirely different lines. This is fertile ground for products that claim "trend lines alone are enough to win" while actually selling non-reproducible discretion.

This article covers both the principles and, honestly, the limits.

How to Draw Trend Lines

Rising trend line (support)

In an uptrend, connect low to low. Price bounces off this line repeatedly.

1. Confirm the uptrend via Dow Theory (higher highs and higher lows)
2. Pick a prominent starting low
3. Connect to the next significant low (the bottom of a pullback)
4. Only after a third touch and bounce treat the line as "valid" — two points may be coincidence

Falling trend line (resistance)

In a downtrend, connect high to high. Price is capped at this line repeatedly.

Channel line

Once you have a trend line, draw a parallel line on the opposite side.

• Uptrend: the support line through the lows + a parallel upper line touching the highs
• Downtrend: the resistance line through the highs + a parallel lower line touching the lows

Price tends to oscillate between the two lines (the channel). The textbook use: buy near the lower line (in an uptrend), take profit near the upper line.

What Makes a Trend Line Valid

Not all trend lines carry equal weight. Conditions for a reliable line:

A steep trend line means price is rising at an unsustainable speed. When it breaks, that may not be "downtrend started" — it may be "deceleration to a sustainable pace". Misreading the angle means mistaking a slowdown for a reversal.

Judging a Break

When price breaks a trend line, it hints at a change of trend — but here is the biggest trap: "broke" is ambiguous.

Things to weigh:

• Close basis vs. wick only: a wick poking through that the close recovers may be a fakeout
• Behaviour after the break: did price stay below (above), or snap right back?
• Volume: a surge on the break (more likely real) vs. a break on thin volume
• Retest: if price returns toward the line after breaking and is rejected there, the break is more reliable (old support becomes new resistance)

How to Use It

How to Read

OANDA:USDJPY

Trend-follow: buy the pullback at the channel low

1. Confirm a clear uptrend + a reliable trend line (3+ touches)
2. Wait for price to pull back toward the line
3. If you see signs of a bounce (lower wick, volume increase, a reversal candle), buy
4. Stop just below the line (below the recent higher low)
5. Target around the channel upper line

Not "buy mechanically on touch" but "touch + confirmation of a bounce". This alone avoids most fakeouts.

Reversal: confirm the line break

1. A clear close-basis break of the trend line
2. Ideally a retest confirming "old support → new resistance"
3. Check consistency with Dow structure (a break of the recent higher low)
4. If consistent, treat it as a trend change

Limitations

• No correct way to draw: the line changes with which points you connect, wick vs. body
• Many fakeouts: wick-only breaks especially are unreliable
• Steep lines break fast: the angle requires interpretation
• Useless in ranges: meaningful only when a trend exists
• Requires constant monitoring: useless unless you are watching for the touch

Related Studies

• Dow Theory — the theoretical basis for trend lines
• Support & Resistance — horizontal walls, to be combined with trend lines
• Moving Average — a dynamic trend line of sorts