OpeningMarubozu

Single-bar strong-momentum candle with a long body and no shadow on the open end. White opens right at the low; black opens right at the high. The shaved open shows the move took off from the bell without hesitation.

Quick reference

Field	Value
Family	Candlestick Patterns
Input type	Candle
Output type	f64 — +1.0 white, -1.0 black, 0.0 otherwise
Output range	{-1.0, 0.0, +1.0}
Default parameters	none — OpeningMarubozu::new()
Warmup period	1
Interpretation	Momentum from the open; conviction at the start of the bar

Formula

range = high − low
long body:  |close − open| >= 0.7 · range
white (+1.0): close > open  and  open − low  <= 0.05 · range   (open at the low)
black (-1.0): close < open  and  high − open <= 0.05 · range   (open at the high)

The body must dominate the bar (≥ 70 % of range) and the open end must be effectively shaved (within 5 % of range); the close end may carry a shadow. Thresholds are geometric, not TA-Lib rolling averages. See crates/wickra-core/src/indicators/opening_marubozu.rs.

Parameters

None. Constructed with OpeningMarubozu::new().

Signed ±1 encoding

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

Inputs / Outputs

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

• Always emits a value. Never None; non-matching 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 no-match).

Warmup

warmup_period() == 1 — a single-bar pattern emits from the first candle. Pinned by accessors_and_metadata.

Edge cases

• Shadow on the open end. A white bar that opens above the low (clear lower shadow) yields 0.0 (white_with_lower_shadow_yields_zero); the black mirror is black_with_upper_shadow_yields_zero.
• Short body. A body under 70 % of range is not a marubozu (short_body_yields_zero).
• Zero range. A flat bar yields 0.0 (zero_range_yields_zero).
• Reset. reset() clears the has-emitted flag (reset_clears_state).

Examples

Rust

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

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut m = OpeningMarubozu::new();
    // White: opens at the low (10), small closing shadow above (high 15).
    println!("{:?}", m.update(Candle::new(10.0, 15.0, 10.0, 14.5, 1.0, 0)?));
    // Black: opens at the high (15), small closing shadow below (low 10).
    println!("{:?}", m.update(Candle::new(15.0, 15.0, 10.0, 10.5, 1.0, 1)?));
    Ok(())
}

Output:

Some(1.0)
Some(-1.0)

These match white_opening_marubozu_is_plus_one and black_opening_marubozu_is_minus_one.

Python

import numpy as np
import wickra as ta

o = np.array([10.0, 15.0])
h = np.array([15.0, 15.0])
l = np.array([10.0, 10.0])
c = np.array([14.5, 10.5])

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

Node

const ta = require('wickra');
const m = new ta.OpeningMarubozu();
console.log(m.update(10, 15, 10, 14.5));  // 1
console.log(m.update(15, 15, 10, 10.5));  // -1

Streaming

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

let mut m = OpeningMarubozu::new();
let candle_stream: Vec<wickra::Candle> = Vec::new(); // your live OHLCV candle feed
for bar in candle_stream {
    match m.update(bar) {
        Some(1.0)  => { /* white opening marubozu — bulls seized the open */ }
        Some(-1.0) => { /* black opening marubozu — bears seized the open */ }
        _ => {}
    }
}

Interpretation

1. Conviction at the open. Opening at the extreme and then running shows one side took control immediately — a momentum cue in the body direction, often following an overnight gap or news.
2. Early-session bias. Useful on intraday bars to read who owns the session from the first print.
3. Pair with the close end. Combine with ClosingMarubozu for end-of-bar control, or Marubozu when both ends are shaved.

Common pitfalls

• No direct TA-Lib equivalent. TA-Lib ships CDLMARUBOZU and CDLCLOSINGMARUBOZU but not an opening-marubozu function; this detector completes the pair and will not line up one-to-one with a TA-Lib call.
• Confusing it with a full marubozu. Only the open end is shaved here; a closing shadow is allowed.

References

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

See also

• Marubozu — both ends shaved.
• ClosingMarubozu — the close end shaved instead.
• BeltHold — a related open-at-the-extreme bar.
• Indicators-Overview — the full taxonomy.