Upside Gap Two Crows

Install and import#

npm install fintech-algorithms

import { upsideGapTwoCrows } from "fintech-algorithms/price-action-and-candlesticks/multi-candle-patterns/upside-gap-two-crows";

Signature#

upsideGapTwoCrows(input)

Scans three-bar windows for an up candle, a gapped-up down candle, and a second down candle that opens higher still yet closes back inside the first candle's body.

Parameters#

Returns#

TopicResult

series.matched is the boolean verdict for the window ending at that index, and series.label is "bearish" when it fires and "none" when it does not; this pattern has a single direction. latest carries the last value of each. The warm-up is the two leading bars that cannot close a three-bar window.

Warm-up#

The first 2 bars positions are null. The pattern needs a three-bar window, so both series hold null at indexes 0 and 1 and ready_at is 2. From index 2 onward matched is false or true, and false is a real verdict rather than a warm-up placeholder, so ready_at does not depend on any pattern ever firing. An input of one or two bars returns null throughout, with ready_at null and state "waiting".

Errors#

• When a bar has a non-finite price or volume, a negative volume, a high below its own open/low/close, a low above them, or a timestamp that does not advance — throws Error
• When tick_tolerance or doji_body_ratio is out of range, which the family validates before the branch runs even though this topic does not use either — throws Error
• When input is not an object, input.parameters is not an object, or bars is not an array holding at least one bar — throws Error

Complexity: time O(n), space O(n).

Worked example#

executed Captured by running this function on the input its own test provides. Real output of real code — but not asserted against a published figure.

Input#

{
  "bars": [
    {
      "timestamp": "2024-01-02",
      "basis": "synthetic-unadjusted",
      "open": 100,
      "high": 101.45,
      "low": 98.695,
      "close": 100,
      "volume": 750000,
      "benchmark": 200
    },
    {
      "timestamp": "2024-01-03",
      "basis": "synthetic-unadjusted",
      "open": 101.49111452,
      "high": 103.38381693,
      "low": 100.05480022,
      "close": 101.78791214,
      "volume": 795117,
      "benchmark": 200.56326135
    },
    {
      "timestamp": "2024-01-04",
      "basis": "synthetic-unadjusted",
      "open": 102.45519048,
      "high": 104.6701838,
      "low": 100.91147007,
      "close": 102.9549389,
      "volume": 840234,
      "benchmark": 201.11020913
    }
  ],
  "parameters": {}
}

Call#

upsideGapTwoCrows(input)

Returns#

object with 9 fields: topic_id, title, state, ready, ready_at, series, latest, parameters, …

{
  "topic_id": "D06-F04-A12",
  "title": "Upside Gap Two Crows",
  "state": "calculated",
  "ready": true,
  "ready_at": 2,
  "series": {
    "label": [null, null, "none", "none", "none", "none"],
    "matched": [null, null, false, false, false, false]
  },
  "latest": {
    "label": "none",
    "matched": false
  },
  "parameters": {},
  "diagnostics": {
    "causal": true,
    "input_count": 96
  }
}

Diagrams#

Calculation flow#

flowchart LR
    A["an ordered OHLC sequence, tick size, gap policy, body scal"] --> B["Validate order, basis, and finite values"]
    B --> C["Apply the selected Upside Gap Two Crows convention"]
    C --> D["Emit value, readiness, and diagnostics"]
    D --> E["Interpret descriptively; test outcomes separately"]
    B -->|invalid or insufficient| X["Withhold output with a reason"]

stateDiagram-v2
    [*] --> Waiting
    Waiting --> Ready: enough valid causal observations
    Waiting --> Rejected: malformed or unsupported input
    Ready --> Calculated: selected formula applied
    Calculated --> Interpreted: diagnostic and limitation retained
    Interpreted --> Ready: next observation arrives
    Rejected --> Waiting: corrected input and deterministic reset

How it works#

This page states the contract — how to call it correctly. The article explains the concept: why it works, and where it breaks.

Read the article →

References#

• TA-Lib pattern-recognition catalog — see linked primary or authoritative record
• CME Group candlestick chart lesson — see linked primary or authoritative record
• Japanese Candlestick Charting Techniques — see linked primary or authoritative record
• Evidence decision
• Level 1 evidence map

The rest of the Multi-Candle Patterns family#

• Morning StarEvaluates exactly three candles against explicit morning-star gap, penetration, scale, and downtrend conventions.
• Evening StarEvaluates exactly three candles against explicit evening-star gap, penetration, scale, and uptrend conventions.
• Three White SoldiersEvaluates exactly three candles against explicit white-soldiers body, close, shadow, scale, and downtrend conventions.
• Three Black CrowsEvaluates exactly three candles against explicit black-crows body, close, shadow, scale, and uptrend conventions.
• Three Inside Up/DownEvaluates exactly three candles against explicit inside-pair containment, confirmation, scale, and trend-context conventions.
• Three Outside Up/DownEvaluates exactly three candles against explicit outside-pair engulfing, confirmation, scale, and trend-context conventions.
• Abandoned BabyEvaluates exactly three candles against explicit abandoned-baby isolation, doji, penetration, scale, and context conventions.
• Morning Doji StarScans three-bar windows for a down candle, then a doji, then an up candle that closes above the midpoint of the first candle's …
• Evening Doji StarScans three-bar windows for an up candle, then a doji, then a down candle that closes below the midpoint of the first candle's …
• Three-Line StrikeScans four-bar windows for three same-colour candles followed by one opposite candle whose body swallows the run from the first…
• Rising/Falling Three MethodsScans five-bar windows for a long candle, three bars whose ranges stay inside it, and a fifth candle of the same colour that cl…
• Mat HoldScans five-bar windows for an up candle, a gap above its close, three bars that hold above the first candle's body floor, and a…