Candlestick Chart

A candlestick chart displays four prices per time period: the open, high, low, and close, drawn as a rectangular body with thin wicks above and below. The body spans open to close; the wicks mark the session's extremes. A close above the open prints a green (or white) candle, a close below the open prints red (or black).

One candle compresses the whole session's fight between buyers and sellers into a single shape. A tall green body with no upper wick means buyers controlled the bar start to finish. A long upper wick on the same green body means the rally was sold into. That extra information is why candlesticks displaced plain line charts, which only show closes.

Candlestick patterns like the doji, hammer, and engulfing candle are read from these shapes. They describe what already happened; whether the next bar cooperates is a matter of odds, not certainty.