Trendline

A trendline is a hand-drawn boundary of a trend. In an uptrend it touches higher swing lows. In a downtrend it touches lower swing highs. It is a description of the slope the swings have been respecting. It is not a law.

Two points draw the line. A third touch is what makes it interesting. More touches, without cutting through price, raise the chance that other traders see the same line. A line you have to redraw after every bar was never a level.

Use obvious swings, not candle bodies you picked to make the line work. On a log chart the line is a constant percentage slope. On a linear chart it is a constant price slope. Say which you used.

A break of a well-touched trendline is a warning that the slope changed. It is not, by itself, a reversal. Pair it with a broken higher low or lower high. Some traders buy the third touch, with a stop beyond the line.

Cutting through candles to force a touch, using only two points and calling it confirmed, and moving the line after the break so that it was "never broken."

Trendlines are subjective. Two honest analysts will draw different ones. The swing structure underneath the line is less subjective, so give it priority when they disagree.