Zone width around the London open
Sterling pairs and UK indices often print overlapping noise in the first sixty minutes after the cash open. A single-price horizontal drawn from yesterday’s low will be tagged, pierced, and debated before the tea break.
In Practice Lab we measure zone width from the cluster of closes and wicks that actually formed the turn, not from the extreme tick. For a London-open map, that often means a band wide enough to hold the opening auction’s scatter. The band is still a decision: too wide and it excuses every touch; too thin and it pretends the open was orderly.
A useful check: if the first hour spends continuously through your zone without a pause, the zone was aspirational. Widen or remove it before the next session. Mapping after the fact to rescue a broken hairline teaches the wrong lesson.