Use comparable turning points to build the boundaries
Select meaningful peaks and troughs on a single timeframe, with more than one observation supporting each boundary. Record whether the lines use candle extremes or closing prices. A line fitted through convenient points after a breakout can make an untidy range appear more predictive than it was.
Ascending and descending shapes carry familiar directional interpretations, yet either can fail. For a symmetrical triangle, contraction by itself offers no necessary directional answer. A completed close beyond a previously defined boundary adds new evidence. The subsequent reaction indicates whether the move is holding or returning inside.
Measure the narrowing before checking the exit
Assume successive daily peaks are 110, 107 and 104 dollars while corresponding troughs are 90, 94 and 98. The observed high-to-low span contracts from 20 to 6 dollars, a 70% reduction. Suppose the projected upper boundary on the next session is 103.50. A high of 104.20 and close at 103.00 does not pass an illustrative close-above-boundary rule. A later completed close at 104.50 may pass the then-current boundary, provided that boundary was projected in advance. Each sloping line has a value specific to its date.
The apex is geometry, not a deadline
A pattern can drift sideways beyond the expected convergence point or produce false exits in both directions. A narrowing range does not guarantee a large move or an attractive trading outcome after costs. Measured-height projections are conventions rather than promises. News and opening gaps may overwhelm an orderly-looking structure.
Record the line value on the breakout date
On an available completed daily, weekly or monthly chart, freeze the anchor points and calculate where each boundary falls on the candle under review. Record the close and the next reaction, retaining failed exits as well as continuing moves. If compatible volume is available separately, compare it with a stated baseline without treating higher activity as proof of direction.
Primary sources
Sources explain the mechanics and limitations; the editorial examples use invented numbers rather than market quotations.
Your next practical step
Inspect a narrowing structure and compare its dated boundaries with completed closing prices.
Open the first-chart instructions ↗