Tweezer (Top / Bottom)

Two-bar reversal pattern where two consecutive candles share an extreme. Tweezer Top: matched highs at the top of an uptrend (bearish reversal); Tweezer Bottom: matched lows at the bottom of a downtrend (bullish reversal). Visualises rejection of a level.

Quick reference

Item	Value
Family	Candlestick Patterns
Input type	Candle
Output type	f64 — +1.0 Bottom, -1.0 Top, 0.0 otherwise
Output range	{-1.0, 0.0, +1.0}
Default parameters	tolerance = 0.001 (10 bps relative)
Warmup period	2
Interpretation	Reversal candidate signal at trend extremes

Formula

tol_high = tolerance · |prev.high|
tol_low  = tolerance · |prev.low|

tweezer_top    = |curr.high - prev.high| <= tol_high   ->  -1.0
tweezer_bottom = |curr.low  - prev.low|  <= tol_low    ->  +1.0
both           = -> +1.0 (bottom wins by convention)
otherwise      = 0.0

See crates/wickra-core/src/indicators/tweezer.rs.

Parameters

Name	Type	Default	Constraint	Description
tolerance	f64	0.001	finite, [0, 1)	Relative tolerance for matching extremes (1.0 = 100%).

Tweezer::new returns Error::InvalidPeriod for out-of-range tolerance.

Signed ±1 encoding

This pattern already emits the uniform candlestick sign convention shared across the family — +1.0 bullish, −1.0 bearish, 0.0 no pattern — so it drops straight into a machine-learning feature matrix where the bullish and bearish variants of the pattern occupy a single dimension.

Inputs / Outputs

Indicator<Input = Candle, Output = f64>. Python: Tweezer(tol).batch(open, high, low, close); Node: same.

Warmup

warmup_period() == 2. First bar returns 0.0.

Edge cases

• Both extremes match. Tweezer Bottom wins by convention (bullish rejection of the low takes priority).
• Tolerance scaling. tolerance = 0.001 = matching extremes within 10 basis points of each other (relative to the prior extreme). For low-priced instruments you may want larger tolerance to avoid filtering false-positives by noise.
• Reset. Clears the previous-bar cache.

Examples

Rust

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

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Tweezer Bottom: two bars with same low
    let b1 = Candle::new(100.5, 101.0, 99.5, 100.0, 1.0, 0)?;
    let b2 = Candle::new(100.2, 101.5, 99.5, 101.0, 1.0, 1)?;
    let mut tw = Tweezer::new();
    tw.update(b1);
    println!("{:?}", tw.update(b2));  // +1.0
    Ok(())
}

Python

import numpy as np
import wickra as ta

o = np.array([100.5, 100.2])
h = np.array([101.0, 101.5])
l = np.array([ 99.5, 99.5])
c = np.array([100.0, 101.0])

tw = ta.Tweezer(0.001)
print(tw.batch(o, h, l, c))

Node

const wickra = require('wickra');
const tw = new wickra.Tweezer(0.001);
console.log(tw.batch([100.5, 100.2], [101, 101.5], [99.5, 99.5], [100, 101]));

Streaming

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

let mut tw = Tweezer::new();
let candle_stream: Vec<wickra::Candle> = Vec::new(); // your live OHLCV candle feed
for bar in candle_stream {
    if tw.update(bar) == Some(1.0) { /* Tweezer Bottom */ }
    if tw.update(bar) == Some(-1.0) { /* Tweezer Top */ }
}

Interpretation

• Rejection of a level. Two bars probing the same extreme signals significant supply (Top) or demand (Bottom) at that level. Often forms at swing pivots or near round-number support / resistance.
• At trend extremes. Tweezer Bottom at the end of a downtrend = strong reversal candidate. Same shape in a range = noise.
• Pair with confirmation. Don't trade Tweezer alone; require the next bar to confirm direction.

Common pitfalls

• Wrong tolerance. Too tight = no signals; too loose = noise. Calibrate to the instrument's tick / price unit.
• Trading without context. Tweezer mid-range is a coincidence, not a signal. Trend / extreme context is essential.

References

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

See also

• Engulfing — stronger two-bar reversal.
• Harami — opposite two-bar pattern (inside body).
• PiercingDarkCloud — gap-and-fade reversal.
• Indicators-Overview — full taxonomy.