OnNeck

Two-bar bearish continuation. In a decline a long black candle is followed by a white candle that opens below the black bar's low yet rallies only as far as the black bar's low (the "neckline"). The feeble bounce shows sellers remain in control.

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 — OnNeck::new()
Warmup period	2 (first bar always 0.0)
Interpretation	Bearish continuation; the weakest of the neck-line bounces

Formula

long body = |close − open| >= 0.5 · (high − low)
bar1 black & long
bar2 white, opens below bar1's low:       open2 < low1
bar2 closes at bar1's low (the neckline):  |close2 − low1| <= 0.05 · range1

Bearish-only (never +1.0). The bounce dies exactly at the prior low. Ranked by how far the bounce recovers: On-Neck (to the low) < InNeck (just into the body) < Thrusting (toward mid-body) < piercing (past mid-body, a reversal). See crates/wickra-core/src/indicators/on_neck.rs.

Parameters

None. Constructed with OnNeck::new().

Signed ±1 encoding

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

Inputs / Outputs

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

• Close into the body. A second close that recovers into the black body is In-Neck/Thrusting/piercing, not On-Neck (close_into_body_yields_zero).
• Second bar must be white and open below the low. Otherwise 0.0 (second_bar_black_yields_zero, opens_above_low_yields_zero).
• Reset. reset() clears the one-bar cache (reset_clears_state).

Examples

Rust

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

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut t = OnNeck::new();
    println!("{:?}", t.update(Candle::new(15.0, 15.1, 9.0, 10.0, 1.0, 0)?)); // long black, low 9
    println!("{:?}", t.update(Candle::new(7.0, 9.1, 6.9, 9.0, 1.0, 1)?));    // white, closes at 9
    Ok(())
}

Output:

Some(0.0)
Some(-1.0)

The white bar opens at 7.0 (below the black low 9.0) and closes right at the neckline 9.0 — an on-neck. This matches on_neck_is_minus_one.

Python

import numpy as np
import wickra as ta

o = np.array([15.0, 7.0])
h = np.array([15.1, 9.1])
l = np.array([9.0,  6.9])
c = np.array([10.0, 9.0])

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

Node

const ta = require('wickra');
const t = new ta.OnNeck();
t.update(15, 15.1, 9, 10);
console.log(t.update(7, 9.1, 6.9, 9)); // -1

Streaming

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

let mut t = OnNeck::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) { /* weak bounce — downtrend continuation */ }
}

Interpretation

1. Failed bounce. A rebound that stalls at the prior low shows sellers still dominant — bearish continuation in a downtrend.
2. Weakest of the family. The shallower the recovery, the more bearish; On-Neck is the shallowest. Compare with InNeck and Thrusting.
3. Confirm with the trend. Only meaningful inside a decline.

Common pitfalls

• Deeper close. A close into or past the body is a different (less bearish) neck-line pattern or an outright reversal.
• No downtrend context. Continuation patterns need an existing trend.

References

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

See also

• InNeck — bounce just into the body.
• Thrusting — bounce toward mid-body.
• PiercingDarkCloud — the reversal past mid-body.
• Indicators-Overview — the full taxonomy.