This entry is part of the Chart Index, the reference library for the Chart Design Field Guide.

The candlestick chart is the financial markets' native time-series form. Where a line chart shows a single value per period, a candlestick shows four: open, high, low, close. Each period becomes a small graphic — a candle with a body and two wicks — and the colour and shape of the candle encodes whether the period was up or down and how volatile it was.

The form is centuries old. Japanese rice traders in the 18th century, Munehisa Homma in particular, developed it as a way to read the psychology of a market session, not just its result. Modern algorithmic trading has not displaced it; if anything, it has reinforced candlesticks as the universal visual language of price action.

What it is

A candlestick chart maps a time dimension to position along the x-axis and price to position along the y-axis. Each time period (a day, an hour, a minute) is rendered as a vertical rectangle (the body) bounded by the open and close, with thin lines (wicks or shadows) extending to the high and low. The body is filled or coloured to indicate whether the close was above (up) or below (down) the open.

The hero chart above is thirty sessions of the ASX 200. Green candles closed above their open, red ones below; the wicks reach to each session's high and low. The eye reads three things at once: the trend (the index climbs some three hundred points across the six weeks even though red and green sessions alternate most of the way), the volatility (long wicks on the sessions where the index swung intraday and came back), and the rhythm — small bodies after a large move are a market pausing. Randomise it and each session's open and close are jittered while its high and low are re-attached outside them, so every candle stays a well-formed candle.

When to use it

Candlestick charts are the right choice when:

  • The data has explicit open / high / low / close per period — exchange-traded prices, auction outcomes, periodic auctions.
  • The reader's question is "what was the price action like?" — direction, volatility, intra-period range.
  • The audience is financial / trading literate — candlesticks are domain-specific.
  • You have moderate density (20–200 candles per chart). Beyond ~300, candles become wicks.

When not to use it

  • Single-value series. If you only have one value per period (a closing price, an index level), use a line chart. The four-value structure is essential to the form.
  • Continuous markets without discrete periods. A high-frequency cross-market price needs a different form — perhaps tick chart or footprint.
  • Non-financial data. Stretching candlesticks to non-OHLC data is a category error; the visual convention is too strongly associated with markets.
  • Audiences unfamiliar with the form. Casual readers see a bar chart with extra lines. Either accompany with a clear legend or use a line chart of closes.
The same thirty sessions as closing prices
A line of closes carries the trend and nothing else. Every session's range, and whether it opened high and sold off or opened low and rallied, is gone. For a non-trading audience that is often the right trade.

Design principles

Make the body weight bigger than the wick

The body — the open-to-close range — is the most important part. It needs to read as a rectangle, not a stripe, while the wicks stay hairlines. The two figures below are the same twenty sessions; only the band padding differs.

Bodies too thin: candles collapse into ticks
With the band padding at 0.85 the bodies are barely wider than the wicks. Colour still tells up from down, but the open-to-close range — the thing the body exists to show — is unreadable.
Bodies at a readable weight
The same sessions at the default padding. Each body is a clear block, so the size of the day's net move can be compared across sessions at a glance, and the wicks still read as the hairlines they are.

Use the colour convention your audience expects

Western charts default to green-up / red-down, and that is the house default: the matched-lightness green and red from the palette, so neither polarity dominates. Japanese sources default to white-up / black-down. If publishing for a mixed audience, or one where red and green cannot be told apart, pick a neutral pair and say so in the subtitle.

A colour-blind-safe pair: blue up, orange down
The same twenty sessions with the palette's blue and orange standing in for green and red. The information is identical; the mapping is stated in the title because it is not the one most readers expect.

Show enough candles to read the trend

A candlestick chart with five candles is just five glyphs. The form needs density to convey rhythm: 30–100 candles per chart is the readable range.

Five sessions
Five glyphs. Each can be read on its own, but there is no rhythm to read across them — no run, no pause, no reversal.
Sixty sessions
Sixty candles. Now there is a story: a grinding rise, a volatile stretch in the mid-thirties with long lower wicks as buyers stepped in on every dip, a run to new highs, and a slide on the last few sessions. None of that exists in five candles.

Use a volume sub-panel

Most candlestick charts have a small bar chart of volume beneath the price panel, sharing the x-axis. Volume gives context: a big body on heavy volume is a meaningful move; the same body on light volume is noise. The house renderer draws the two as separate figures on the same session labels.

Price: twelve sessions around a results announcement
Session 7 is the results day — the largest body on the chart, closing near its high.
Volume: the same twelve sessions
Session 7 traded four times the usual volume. The big candle above it is a move the market participated in, not a thin-market spike; the small bodies that follow on ordinary volume are the price settling at its new level.

Add moving averages sparingly

Overlaying a moving average (or two) on candlesticks helps the eye see trend through the noise. Two MAs is the maximum — more starts to compete with the candles for attention.

Annotate notable events

Earnings dates, regulatory announcements, technical pattern recognitions — these are best marked with a thin vertical guide and a short label. Do not let the annotation dominate the candles.

Resist the urge to use for patterns

Candlestick patterns (hammer, doji, engulfing, etc.) have a long literature in technical analysis. The chart can show them, but the form's job is to display price action faithfully. Pattern recognition is the reader's job (and statistical literature shows the recognition is often retrospective).

Anatomy

The composition of a candlestick chart
An anatomical guide

A candlestick chart's anatomy is a row of body-plus-wick glyphs, each encoding four numbers in a few square pixels. Body colour carries direction, body length the net move, wick length the range. The visual language is rich, conventional, and read at a glance by trained eyes.

  • OHLC bar — same four data points, encoded as horizontal ticks rather than a body. Equally information-dense; less visually distinctive.
  • Line chart — closing price only. Smoother, less information per period.
  • Box plot — the same body-and-whisker grammar applied to a distribution rather than a session.
  • Heikin-Ashi — a smoothed candlestick variant that averages adjacent periods.
  • Point and figure — non-time-based price chart for trend trading.
  • Renko / Kagi — price-movement-based bars; ignore time entirely.

Reading list

  • Nison, S. (1991). Japanese Candlestick Charting Techniques. The standard Western reference.
  • Murphy, J. (1999). Technical Analysis of the Financial Markets. Candlesticks in context.
  • Lo, A., Mamaysky, H. & Wang, J. (2000). Foundations of Technical Analysis. On the statistical reality of pattern recognition.