http://stockcharts.com/school/doku.php?id=chart_school:chart_analysis:heikin_ashi The Heikin-Ashi Open is the average of the prior Heikin-Ashi candlestick open plus the close of the prior Heikin-Ashi candlestick. HA-Open = (HA-Open(-1) + HA-Close(-1)) / 2