StalledPattern

Three-bar bearish reversal warning (also called Deliberation). Two long white candles push higher, then a small-bodied white candle opens at or near the top of the second body and barely advances — the rally is running out of breath.

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 — StalledPattern::new()
Warmup period	3 (first two bars always 0.0)
Interpretation	Bearish exhaustion warning near the top of an advance

Formula

long body  = |close − open| >= 0.5 · range
small body = |close − open| <= 0.3 · range
bar1, bar2 long white;  bar3 small white
rising closes:  close3 > close2 > close1
bar3 rides the shoulder:  open3 >= close2 − 0.1 · (high2 − low2)

Bearish-only (never +1.0). After two strong white candles, the small white third candle perched on the second's shoulder shows buyers losing momentum. Thresholds are geometric, not TA-Lib rolling averages. See crates/wickra-core/src/indicators/stalled_pattern.rs.

Parameters

None. Constructed with StalledPattern::new().

Signed ±1 encoding

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

Inputs / Outputs

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

• All three must be white & rising. A black bar (non_white_yields_zero) or non-ascending closes (non_rising_closes_yield_zero) yields 0.0.
• Leading bodies must be long. Short first/second bodies → 0.0 (short_first_bodies_yield_zero).
• Third body must be small and on the shoulder. A large third body (large_third_body_yields_zero) or a third candle that opens well below the second close (third_bar_off_shoulder_yields_zero) yields 0.0.
• Zero range. A flat bar yields 0.0 (zero_range_yields_zero).
• Reset. reset() clears the two-bar cache (reset_clears_state).

Examples

Rust

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

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut t = StalledPattern::new();
    println!("{:?}", t.update(Candle::new(10.0, 12.05, 9.9, 12.0, 1.0, 0)?));  // long white
    println!("{:?}", t.update(Candle::new(11.0, 14.05, 10.9, 14.0, 1.0, 1)?)); // long white
    println!("{:?}", t.update(Candle::new(14.0, 14.6, 13.95, 14.15, 1.0, 2)?));// small white, stalls
    Ok(())
}

Output:

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

The third candle is a small white body (0.15 of a 0.65 range) opening at 14.0 on the second candle's shoulder (close2 = 14.0) and barely advancing — a stalled pattern. This matches stalled_pattern_is_minus_one.

Python

import numpy as np
import wickra as ta

o = np.array([10.0, 11.0, 14.0])
h = np.array([12.05, 14.05, 14.6])
l = np.array([9.9,  10.9, 13.95])
c = np.array([12.0, 14.0, 14.15])

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

Node

const ta = require('wickra');
const t = new ta.StalledPattern();
t.update(10, 12.05, 9.9, 12);
t.update(11, 14.05, 10.9, 14);
console.log(t.update(14, 14.6, 13.95, 14.15)); // -1

Streaming

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

let mut t = StalledPattern::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) { /* rally stalling — tighten longs / watch for a top */ }
}

Interpretation

1. Loss of momentum. Two strong up candles followed by a tiny one on the shoulder shows demand thinning — a warning of a possible top, not a confirmed reversal.
2. Warning, not trigger. Like Advance Block, it argues for caution on longs rather than an outright short; wait for a bearish confirmation candle.
3. Best near resistance. Most meaningful at the top of an extended advance or into resistance.

Common pitfalls

• Expecting an immediate drop. "Stalled" means momentum is fading, not that price reverses on the next bar.
• Confusing it with Advance Block. Both are deliberation tops; AdvanceBlock emphasises shrinking bodies with rising shadows across all three, while StalledPattern keys on the small third candle riding the shoulder.

References

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

See also

• AdvanceBlock — sibling deliberation top.
• ThreeSoldiersOrCrows — the healthy three-soldier advance this pattern warns is tiring.
• Indicators-Overview — the full taxonomy.