UpsideGapTwoCrows

Three-bar bearish reversal after an advance. Two black candles gap up above a long white candle; the second black candle engulfs the first crow yet still closes above the white body, leaving the upside gap open — a more strictly-defined cousin of Two Crows.

Quick reference

Field	Value
Family	Candlestick Patterns
Input type	Candle
Output type	f64 — -1.0 bearish, 0.0 otherwise (never +1.0)
Output range	{-1.0, 0.0}
Default parameters	none — UpsideGapTwoCrows::new()
Warmup period	3 (first two bars always 0.0)
Interpretation	Bearish reversal warning at the top of an advance

Formula

bar1 green (long white)
bar2 red & its body gaps up above bar1's body:  bar2.close > bar1.close
bar3 red & opens above bar2's open:              bar3.open  > bar2.open
         & closes below bar2's close:            bar3.close < bar2.close
         & closes above bar1's close:            bar3.close > bar1.close

Bearish-only (never +1.0). Unlike TwoCrows, the second crow engulfs the first but the gap above the white body is not filled — the close stays above the white close. Thresholds are geometric, not TA-Lib rolling averages. See crates/wickra-core/src/indicators/upside_gap_two_crows.rs.

Parameters

None. Constructed with UpsideGapTwoCrows::new().

Signed ±1 encoding

Single-direction shape: −1.0 bearish, 0.0 no pattern — one feature-matrix dimension.

Inputs / Outputs

use wickra::{Indicator, UpsideGapTwoCrows, Candle};
// UpsideGapTwoCrows: Input = Candle, Output = f64
const _: fn(&mut UpsideGapTwoCrows, Candle) -> Option<f64> = <UpsideGapTwoCrows as Indicator>::update;

• Always emits a value. Never None; warmup and no-match bars return 0.0.
• Node. update(open, high, low, close) → number; batch(open, high, low, close) → Array<number>.
• Python. update(candle) → float; batch(open, high, low, close) → 1-D numpy.ndarray (0.0 on warmup / no-match).

Warmup

warmup_period() == 3. The first two bars return 0.0 (first_two_bars_return_zero, accessors_and_metadata).

Edge cases

• Gap must stay open. A third candle that closes back into the white body (filling the gap) yields 0.0 (closing_the_first_gap_yields_zero).
• No upside gap. Without the initial body gap up the result is 0.0 (no_gap_up_yields_zero).
• Reset. reset() clears the two-bar cache (reset_clears_state).

Examples

Rust

use wickra::{Candle, Indicator, UpsideGapTwoCrows};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut t = UpsideGapTwoCrows::new();
    println!("{:?}", t.update(Candle::new(10.0, 12.2, 9.9, 12.0, 1.0, 0)?));  // long white
    println!("{:?}", t.update(Candle::new(14.0, 14.2, 12.9, 13.0, 1.0, 1)?)); // black, gaps up
    println!("{:?}", t.update(Candle::new(15.0, 15.2, 12.4, 12.5, 1.0, 2)?)); // black, engulfs, gap holds
    Ok(())
}

Output:

Some(0.0)
Some(0.0)
Some(-1.0)

The second crow opens at 15.0 above the first crow's open 14.0 and closes at 12.5 — below the first crow's close 13.0 but still above the white close 12.0, so the gap holds. This matches upside_gap_two_crows_is_minus_one.

Python

import numpy as np
import wickra as ta

o = np.array([10.0, 14.0, 15.0])
h = np.array([12.2, 14.2, 15.2])
l = np.array([9.9,  12.9, 12.4])
c = np.array([12.0, 13.0, 12.5])

print(ta.UpsideGapTwoCrows().batch(o, h, l, c))  # [ 0.  0. -1.]

Node

const ta = require('wickra');
const t = new ta.UpsideGapTwoCrows();
t.update(10, 12.2, 9.9, 12);
t.update(14, 14.2, 12.9, 13);
console.log(t.update(15, 15.2, 12.4, 12.5)); // -1

Streaming

use wickra::{Candle, Indicator, UpsideGapTwoCrows};

let mut t = UpsideGapTwoCrows::new();
let candle_stream: Vec<wickra::Candle> = Vec::new(); // your live OHLCV candle feed
for bar in candle_stream {
    if t.update(bar) == Some(-1.0) { /* bearish warning — gap above intact but crows gathering */ }
}

Interpretation

1. Reversal warning at the highs. Two black candles above a strong white one, with the second engulfing the first yet the gap still open, signals distribution at the top of an advance.
2. Confirmation needed. Because the gap is unfilled the signal is a warning, not a confirmed turn; wait for a close back into the white body.
3. Compare with Two Crows. TwoCrows fills the gap; this one keeps it open and is the rarer, stricter variant.

Common pitfalls

• Treating the held gap as bullish. The open gap is bearish here — it sits above a stalling advance.
• No uptrend context. Only meaningful after an advance.

References

• Steve Nison, Japanese Candlestick Charting Techniques (1991).

See also

• TwoCrows — the gap-filling sibling.
• PiercingDarkCloud — two-bar top reversal.
• Indicators-Overview — the full taxonomy.