A recording chart of the type carried as one of a stacked array on a chart-driving and changing mechanism which functions periodically to separate the top chart from the stacked array. A zonal portion of the chart adjacent to a slit is integrally deformed to provide an open-ended socket or slot in the chart to facilitate intrusive penetration of a blade-like lip of a rotatable release button or hub of the chart changer, cleanly, between a top chart of the stack and a chart therebeneath, to lift and displace the chart while preventing the release button from cutting into the top chart itself adjacent a blade-facing edge thereof.