The Heikin-Ashi (meaning "average bar" in Japanese) is a modified candlestick chart where the open-high-low-close (OHLC) values take the previous period into account to better isolate trends.
Except for the calculation method, all other features of the Heikin-Ashi are the same as normal candlestick charts. (OHLC bars are set apart by a time series defined by the user; up periods are shown with empty bars; down periods are shown with filled bars; and so on.)

The Heikin-Ashi OHLC values are calculated from midprice values as follows:
The midpoint of the Heikin-Ashi open and close values for the previous bar.
The high (or the Heikin-Ashi Open if it was higher).
The low (or the Heikin-Ashi Open if it was lower).
The average of four bar prices: open, high, low, and close.
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