What a candlestick shows

A candlestick is one time interval drawn from four prices: the first price, the highest price, the lowest price, and the last price. The body is the distance from the open to the close. The wicks are prices beyond that body.

The four prices

The open is the first price in the interval. The close is the last price. The high is the highest price reached while the interval was open, and the low is the lowest. A vendor that publishes candlestick data returns those prices together. In the Binance spot kline response, each bar is identified by its open time and then lists the open, the high, the low, the close, and the volume, as the kline fields show.

Volume counts how much was traded. It is not one of the four prices, and it does not change the shape of the body.

Color is a chart choice. Many charts paint an up close in one color and a down close in another. The definition is the four prices. Two charts can use different colors for the same bar.

Body and wicks

The body connects the open and the close. If the close is above the open, the body marks a rise. If the close is below the open, the body marks a fall. The upper wick runs from the top of the body up to the high, when the high is beyond the body. The lower wick runs from the bottom of the body down to the low, when the low is beyond the body.

A worked example makes the parts easy to check. These figures are a worked example, not a recorded run.

Both bars open at 100.

The first bar trades as high as 105 and as low as 94, then closes at 96. The body runs from 100 down to 96, which is 4 points. The upper wick runs from the open at 100 up to 105. The lower wick runs from the close at 96 down to 94. The full range is 105 minus 94, which is 11.

The second bar trades as high as 108 and as low as 97, then closes at 104. The body runs from 100 up to 104, which is 4 points. The upper wick runs from 104 up to 108. The lower wick runs from 100 down to 97. The full range is 108 minus 97, which is 11.

The bodies are the same size. The closes are on opposite sides of the open. That is the difference the picture is for.

What Tradee stores

Tradee stores each candle as an open time plus the open, high, low, close, and volume. The close time is the open time plus the length of the timeframe. It is computed when the bar is read.

A bar that has not finished can still change its high, its low, and its close. Using the eventual close before the interval ends treats a future price as if it were already known. A forming candle is not a closed candle is the page for that timing.

A bar is a record, not a decision

The candlestick says where price traded during the interval. It does not say to buy, to sell, or to stay out. A named pattern is still a description of one or more bars. A strategy is the later decision: the entry, the exit, and the stop. An indicator is not a strategy walks through that split.

If you want to build a rule on closed bars, start with a first strategy after the four prices are familiar.