Counterattack

Two-bar reversal where the second bar storms back to close right where the first closed. A long candle runs with the trend, then an opposite-coloured long candle opens far in the trend direction and rallies (or sells off) all the way back to the prior close — the two level closes form the "counterattack line".

Quick reference

Field	Value
Family	Candlestick Patterns
Input type	Candle
Output type	f64 — +1.0 bullish, -1.0 bearish, 0.0 otherwise
Output range	{-1.0, 0.0, +1.0}
Default parameters	equal_tolerance = 0.05 (TA-Lib "equal" factor); bindings use the default
Warmup period	2 (first bar always 0.0)
Interpretation	Two-bar reversal; matching closes mark the line

Formula

long bodies = |close − open| >= 0.5 · (high − low)   (both bars)
equal closes = |close2 − close1| <= equal_tolerance · mean(range1, range2)
bullish (+1.0): bar1 black (down), bar2 white (up),  equal closes
bearish (-1.0): bar1 white (up),   bar2 black (down), equal closes

The defining feature is the matched close: the counterattack candle erases the session's move and stops exactly at the prior close. See crates/wickra-core/src/indicators/counterattack.rs.

Parameters

Name	Type	Default	Valid range	Source
equal_tolerance	f64	0.05	[0.0, 1.0)	Counterattack::with_tolerance (counterattack.rs)

with_tolerance outside [0, 1) errors (rejects_invalid_tolerance, accepts_valid_tolerance). Python/Node construct with the default.

Signed ±1 encoding

Emits the uniform candlestick sign convention — +1.0 bullish, −1.0 bearish, 0.0 no pattern — a single feature-matrix dimension.

Inputs / Outputs

use wickra::{Indicator, Counterattack, Candle};
// Counterattack: Input = Candle, Output = f64
const _: fn(&mut Counterattack, Candle) -> Option<f64> = <Counterattack 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() == 2. The first bar returns 0.0 (first_bar_returns_zero, accessors_and_metadata).

Edge cases

• Closes must be level. A second close away from the first by more than the tolerance yields 0.0 (unequal_close_yields_zero).
• Colours must oppose. Same-coloured bars yield 0.0 (same_color_yields_zero).
• Both bodies must be long. A short body yields 0.0 (short_body_yields_zero).
• Reset. reset() clears the one-bar cache (reset_clears_state).

Examples

Rust

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

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut t = Counterattack::new();
    println!("{:?}", t.update(Candle::new(20.0, 20.1, 14.9, 15.0, 1.0, 0)?)); // long black, close 15
    println!("{:?}", t.update(Candle::new(10.0, 15.1, 9.9, 15.0, 1.0, 1)?));  // long white, close 15
    Ok(())
}

Output:

Some(0.0)
Some(1.0)

Both bars close at 15.0 with opposite colours and long bodies — a bullish counterattack. This matches bullish_counterattack_is_plus_one.

Python

import numpy as np
import wickra as ta

o = np.array([20.0, 10.0])
h = np.array([20.1, 15.1])
l = np.array([14.9, 9.9])
c = np.array([15.0, 15.0])

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

Node

const ta = require('wickra');
const t = new ta.Counterattack();
t.update(20, 20.1, 14.9, 15);
console.log(t.update(10, 15.1, 9.9, 15)); // 1

Streaming

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

let mut t = Counterattack::new();
let candle_stream: Vec<wickra::Candle> = Vec::new(); // your live OHLCV candle feed
for bar in candle_stream {
    match t.update(bar) {
        Some(1.0)  => { /* bullish counterattack at a low */ }
        Some(-1.0) => { /* bearish counterattack at a high */ }
        _ => {}
    }
}

Interpretation

1. Momentum snap-back. The counterattack candle fully reverses the prior session and halts at its close — a reversal cue when it appears at an extreme.
2. Weaker than piercing/engulfing. Because the second bar only returns to the prior close (not through it), it is softer than a piercing line or engulfing; confirmation matters.
3. Watch the level. The shared close often becomes a near-term pivot.

Common pitfalls

• Demanding identical closes. They only need to match within equal_tolerance (5 % of mean range).
• Confusing with piercing. PiercingDarkCloud pushes into the prior body; a counterattack stops at the prior close.

References

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

See also

• PiercingDarkCloud — stronger two-bar reversal.
• Engulfing — full-body two-bar reversal.
• Indicators-Overview — the full taxonomy.