Candlestick Chart: What One Bar Really Shows
A candlestick chart compresses every trading session into four prices: where it opened, the highest point buyers reached, the deepest level sellers touched, and where it closed. One bar per session. Stack three hundred of them side by side and you can replay a market's whole argument in a few seconds of scrolling.
That density is why the format outlived the rice traders who invented it, and why Vike's engine still reads it today. Every detector we publish, from batch_hammer to batch_doji, is plain arithmetic on those four numbers. Learn what they encode and the pattern pages in this cluster stop looking like folklore.
What a candlestick chart is
Each candle owns a fixed slice of time — a minute, an hour, a day — and states four facts about it. The open and close bound the coloured body: green when the close finished above the open, red when it finished below. Thin lines called shadows, or wicks, stretch from the body to the session's high and low.
A line chart keeps only the close, which throws three of those four facts away. The candle keeps the failures: the rally that faded before the bell, the flush that got bought back. Failures are exactly what patterns are made of, and that is the deep reason nobody builds a pattern detector on closing prices alone.
The four prices behind every bar
Watch one session live and the candle is a moving thing. It is born as a dash at the open. Price wanders, the body stretches and flips colour, and a wick grows every time an extreme gets rejected — then the close freezes the bar into the shape a chartist will read forever after.
Two practical consequences follow. A pattern does not exist until its bar closes; the engine evaluates closed bars only, because half-formed shapes on a live candle evaporate constantly. And the finished shape is a summary, not a story — a long lower shadow proves sellers were beaten back, but never tells you at what hour, or in how many attempts.
Reading the chart bar by bar
Here is the discipline I use: treat each bar as a question about the one before it. Did buyers defend the prior low? Did the close make progress, or stall inside the previous body?
Take the BTC chart above. A run of daily bars slides lower, each close worse than the last — then one session dumps hard and claws the entire loss back, leaving a long lower shadow under a small body. That bar is a hammer, and batch_hammer flags it with three ratio checks: body at most 30% of the range, lower shadow at least twice the body, upper shadow no bigger than the body.
Notice what you just did there. No picture was memorised. You read four prices, compared them against the bars before, and arrived at a statement about who controls the tape. Chart reading is that operation, repeated.
Colour, size, and the timeframe underneath
Every candlestick chart is an aggregation choice. The same tape sliced into daily bars prints different candles than it does sliced hourly, and a pattern can exist on one timeframe while the other shows nothing at all. Neither view is wrong; they answer different questions. The mistake I made early was flipping between timeframes until one of them agreed with me — which is not analysis, it is shopping.
Size is relative too. The engine never asks whether a body is "big" in dollars: batch_doji measures a body against the average of the last ten bodies, so a doji has to be tiny next to its neighbours, not merely small. The BNB candle flagged above is a real one it caught. Colour matters least of all on such bars — a body spanning a rounding error carries no conviction in either direction.
From single bars to patterns
Patterns are short sentences written in this alphabet. One bar with a long lower shadow after a decline is a hammer. A body swallowed whole by the next one is an engulfing. Three green closes marching upward are soldiers. The full cheat sheet lists all fifteen shapes the engine currently ships, each with the exact rule its detector applies on live charts.
Two warnings before you dive in, both earned. Every shape fails often — the pattern pages show real losing trades on purpose, because a sheet without failures is an advert. And no shape means anything without the trend around it, which is the whole subject of how to read candlestick charts, the walkthrough that follows this page.
Frequently asked questions
What do the colours on a candlestick chart mean? Green marks a close above the open, red a close below it. Some platforms draw the same thing as white and black. It is convention, not information — Japanese charts traditionally print rising sessions in red, which is why the bullish three white soldiers translates to "three red soldiers" at home.
Is a candlestick chart better than a line chart? For pattern work, yes, because it preserves each session's rejected extremes — the raw material every detector reads. A line chart remains the cleaner way to eyeball a multi-year trend, precisely because it hides all that texture.
Which timeframe should a beginner read first? Daily. Each bar carries a full session of order flow, the shapes are better tested there, and one glance a day builds the habit. I learned more from a year of daily bars than from any month spent staring at one-minute noise.
Do candlestick charts work for crypto? Yes — every example on this page is real Binance daily data with a real detection on it. Crypto's one structural quirk is the missing overnight gap: markets that never close open each bar exactly on the prior close, which quietly changes how a few classic patterns fire.
This is educational material, not financial advice. Candlestick patterns describe probabilities, not certainties, and every real trade carries real risk — size positions so a wrong read costs little.