OHLC and candlesticks

EN source master • P04 — Trading Foundations • needs_review.

Educational boundary: mechanisms and evidence only. No BUY/SELL/HOLD signal, trade recommendation, personalized investment advice, guaranteed setup, price target, expected profit, guaranteed win rate or guaranteed risk/reward outcome. All examples are ILLUSTRATIVE / FICTIONAL; no real money or live trade is required.

A candle is a compact summary of prices in a specified interval. Its compactness is useful, but also removes information. Reconstructing a candle from raw prints teaches you to identify that loss before using a chart as evidence. A dramatic wick does not identify a trader, show available liquidity or tell you what will happen next.

For this lesson, prices are executed trade prices in fictional quote units (CU) per fictional instrument unit (FU). Open is the first included trade price; high the maximum included price; low the minimum; close the last included price. These are properties of the chosen feed, instrument and bucket. A quote-based or mark-price chart would summarize different inputs. Specify the input basis before comparing charts.

The candle body extends between open and close. Its length is |close − open|. The upper wick runs from max(open,close) to high; the lower wick from low to min(open,close). Total range is high − low. Those three lengths sum to the range. Chart colors are conventions; a legend must explain them. A positive close-minus-open means only that the last included price exceeded the first included price.

Aggregation groups included prints and discards most ordering information. Here a bucket includes its start and excludes its end: [t0,t4). These synthetic minute offsets are not real timestamps. The trade exactly at t4 belongs to the next bucket. Equal-time trades would require an explicit sequence tie-break; this fixture has none. OHLC from chronologically ordered prints is not necessarily the same as OHLC from unsorted input.

An unfinished bucket has a provisional close and provisional extremes. A completed bucket is still limited by feed coverage, corrections and trade eligibility rules. Do not silently fill an absent bucket with zero prices or assume a flat candle proves no activity. First determine whether the feed was complete, the instrument traded, and the provider publishes empty intervals. The primary candle documentation illustrates that providers can omit no-tick intervals.

Source-to-claim scope

• OHLC first/last/extreme executed prices, time buckets and omitted no-tick intervals [S04-CANDLES].
• Body and wick conventions [S04-CHARTS].

The fixture's arithmetic, bucket alignment, strict swing rule, matching/trigger assumptions, journal convention and rubric are explicitly supplied teaching conventions where applicable; these references do not authenticate fictional values or endorse a venue. US securities and futures sources support bounded vocabulary and limitations, not a claim that their rules apply universally to crypto.

• Print: one recorded execution, with sequence and price.
• OHLC (open, high, low, close): first, maximum, minimum and last included prices.
• Body / wick: visual encoding of endpoint difference and extreme excursions.
• Aggregation: transformation from an ordered event series to a bucket summary.
• Intra-candle path: the sequence and timing of events inside the bucket.
• Coverage: which events the source includes; not a universal market view.

Data status: ILLUSTRATIVE / FICTIONAL. This is the complete supplied dataset, not market data. Bucket [t0,t4); price CU/FU. Each included print has quantity 1 FU. Paths are alternatives, never combined.

Both paths produce O100, H104, L98, C102. Body = 2; upper wick = 104 − 102 = 2; lower wick = 100 − 98 = 2; range = 6. Both have four included executions and volume 4 FU. But A reaches the high before the low; B does the reverse. A candle alone cannot resolve that order.

An assumed threshold at 103 and another at 99 are crossed in different orders across these paths. That is a demonstration of ambiguity, not an entry or exit rule. Even knowing a threshold was crossed by a recorded trade would not establish an order fill: queue position, order arrival, executable side and available size are missing.

The candle proves extrema and endpoints of included observations under its definition. It does not prove duration at an extreme, which side initiated a trade, volume at each price, order-book depth, future movement or the intentions of participants. A wick is not a causal explanation.

Treating a green body as a recommendation; calling the high a price at which any size could execute; sorting prices numerically before finding the open; including both boundary prints in adjacent buckets; and reading a completed-candle shape before that candle had actually completed all create false conclusions. Keep raw inputs separate from their visual summary.

Inputs: FIX-P04-01 and the interval rule above. Use paper or a local calculator; no connection or order placement.

Tasks: (1) Compute each path's OHLC and four geometric lengths. (2) Explain whether t4 changes this bucket's high. (3) Compare the order of visits to high and low. (4) Classify the claim “an order at 103 filled” and name the missing evidence. (5) State how your report changes if t2 is missing from path A.

Confirm instrument and price basis; fix bucket boundaries; sort by event order; count included prints; calculate OHLC and geometry; mark incomplete data; and state what the candle omits.

OHLC is a lossy transformation. A correct candle can coexist with several different intra-bucket sequences. Reproducible chart reading begins with the input scope and interval rule, and ends with a bounded claim rather than a financial action.

P04-L01-V01 — annotated candlestick

Educational question: Can different event sequences produce the same candle?

Dataset: FIX-P04-01; ILLUSTRATIVE; observedAt=null. Mechanism sources: S04-CANDLES, S04-CHARTS. Draw the two alternative paths A and B beside identical OHLC candles. Label O100,H104,L98,C102, body 2, each wick2 and range 6; mark the excluded t4 print with an open interval boundary. Do not use trade-signal icons.

Caption: Both fictional paths give the same candle; the order of the high and low is omitted.

Alt text: Two paths 100–104–98–102 and 100–98–104–102 both yield O100 H104 L98 C102.

Layout: 390px stacked labels and accessible equivalent text table; 768px/tablet and desktop verification pending. RTL: RTL layout and native labels for later Arabic adaptation; isolate IDs LTR; preserve chronological direction and numerical price axes. No translation authored. Style: Dark navy with cyan, electric blue and violet; readable contrast and labels independent of color; official ZECOIN branding only. Deterministic chart/SVG/HTML; no fabricated market screenshot.

Status: SPECIFICATION_ONLY; version 1; needs_review. No rendered asset or runtime integration is claimed.

P04-L01-V02 — evidence panel

Educational question: Which conclusions follow from these inputs, and which remain unsupported?

Dataset: FIX-P04-01; ILLUSTRATIVE; observedAt=null. Mechanism sources: S04-CANDLES, S04-CHARTS. Bind four labelled rows OBSERVED / INFERRED / UNKNOWN / INSUFFICIENT EVIDENCE to this lesson's evidence table and record locators. Include one calculation or classification and its assumptions. Display missing data and execution limits explicitly; no financial call or forecast badges.

Caption: Illustrative evidence states under the stated data and execution assumptions.

Alt text: A four-state table distinguishes supplied fictional records, conditional calculations, missing information and unsupported claims.

Layout: 390px stacked labels and accessible equivalent text table; 768px/tablet and desktop verification pending. RTL: RTL layout and native labels for later Arabic adaptation; isolate IDs LTR; preserve chronological direction and numerical price axes. No translation authored. Style: Dark navy with cyan, electric blue and violet; readable contrast and labels independent of color; official ZECOIN branding only. Deterministic chart/SVG/HTML; no fabricated market screenshot.

Status: SPECIFICATION_ONLY; version 1; needs_review. No rendered asset or runtime integration is claimed.

NONE. Use the embedded fixture, paper or an offline worksheet. No paid access, live market feed, real funds, wallet connection, account creation, signatures or trades are needed. No production tool capability is added or asserted.

• S04-CANDLES — Coinbase product candles: https://docs.cdp.coinbase.com/api-reference/exchange-api/rest-api/products/get-product-candles Supports: First/last/extreme trade prices, time buckets and missing intervals; no market observations imported. Checked 2026-09-30; primary page inspected.
• S04-CHARTS — CME chart types: https://www.cmegroup.com/education/courses/technical-analysis/chart-types-candlestick-line-bar Supports: OHLC body and wick conventions only; predictive interpretations are not adopted. Checked 2026-09-30; primary page inspected.

These references support mechanism definitions only. All fixture values, paths, tickets, capital, fills and calculations are original ILLUSTRATIVE / FICTIONAL teaching material, not source-observed prices, a historical performance series or a recommendation for a current market. Documentation examples and official venue names do not endorse a platform. Dataset FIX-P04-01 is bounded to the embedded records and assumptions; observedAt=null because no real-world observation was collected. Future source review and editorial acceptance remain pending: reviewStatus=needs_review, lastReviewedAt=null.

P04-L02 — Timeframes and context. Continue within this program's learning sequence.