1 December 2025 · Nattaya Prasert
Drawing Relative Strength Lines That Actually Hold
A step-by-step pencil method for comparing two sector ETFs on printed charts, including where most traders place the line too early.
Relative strength on paper is a ratio line you construct by comparing closing prices of two symbols over the same weekly dates. You do not need software — a printed table of closes and a ruler are enough.
Plot the ratio on a blank panel beneath the two price charts. Connect two obvious swing lows with a straight edge. Extend the line forward one week beyond the last print date as a tentative guide, not a forecast.
Most traders place the first line too early, using only two weeks of data. Wait for three confirmed weekly closes on one side of the tentative line before ink-ing it dark. Light pencil until then.
When price crosses your line, note the volume week in the margin. Crosses on rising volume get a solid dot; crosses on thin volume get an open circle. That simple code prevents overreaction on Monday opens.
relative strength technique