Reversal is the number of boxes (points) the price has to turn back to initiate a new column. As the name suggests "reversal" implies a change in the current trend. So a running column of "X" will shift to a new column of "O" if the reversal gets triggered. Like box-size the value of reversal is also something debatable and comes often with experience.
Reversal therefore can be 1-point, 2-point, 3-point as many as one wants to keep. A long-term player will always go for a higher value reversal compared to an aggressive trader. However, box in my opinion can be decided independently but reversal is quite dependent on box-size. It's important to have complete understanding of the box size before picking-up the reversal points. Therefore, the reversal point is very important to decide in any chart. Wyckoff used 1-point reversal for his charts. Whereas other great proponents of the art have suggested a standard 3-point reversal.
In the next write-up we would see an interesting and perhaps the most stand-alone characteristics of the P&F chart - price objective.
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