GravestoneDoji

Single-bar bearish reversal. Open, close and low sit at the bottom of the bar while a long upper shadow shows price was pushed up hard and then sold all the way back to the open — sellers rejecting the highs.

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 — GravestoneDoji::new()
Warmup period	1
Interpretation	Bearish rejection of the highs

Formula

range = high − low
doji          = |close − open| <= 0.1 · range
no lower wick = min(open, close) − low  <= 0.1 · range
long upper    = high − max(open, close) >= 0.5 · range

Bearish-only (never +1.0). The mirror is DragonflyDoji. See crates/wickra-core/src/indicators/gravestone_doji.rs.

Parameters

None. Constructed with GravestoneDoji::new().

Signed ±1 encoding

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

Inputs / Outputs

use wickra::{Indicator, GravestoneDoji, Candle};
// GravestoneDoji: Input = Candle, Output = f64
const _: fn(&mut GravestoneDoji, Candle) -> Option<f64> = <GravestoneDoji 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 — emits from the first candle (accessors_and_metadata).

Edge cases

• Lower shadow. A meaningful lower wick yields 0.0 (lower_shadow_yields_zero).
• Short upper shadow. Without the long upper wick the result is 0.0 (short_upper_shadow_yields_zero).
• Not a doji. A real body yields 0.0 (non_doji_yields_zero); 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, GravestoneDoji, Indicator};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut t = GravestoneDoji::new();
    // Body at the bottom (open=close=10, low=9.95), long upper shadow to 14.0.
    println!("{:?}", t.update(Candle::new(10.0, 14.0, 9.95, 10.0, 1.0, 0)?));
    Ok(())
}

Output:

Some(-1.0)

range = 4.05, body 0, lower shadow 0.05, upper shadow 4.0 (> 0.5·range) — a gravestone. This matches gravestone_is_minus_one.

Python

import numpy as np
import wickra as ta

print(ta.GravestoneDoji().batch(
    np.array([10.0]), np.array([14.0]), np.array([9.95]), np.array([10.0])))  # [-1.]

Node

const ta = require('wickra');
const t = new ta.GravestoneDoji();
console.log(t.update(10, 14.0, 9.95, 10)); // -1

Streaming

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

let mut t = GravestoneDoji::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) { /* rejection of the highs */ }
}

Interpretation

1. Top reversal. A long upper shadow sold back to the low is a bearish rejection — strongest at resistance or the top of an advance.
2. Confirm. A single doji is weak evidence; pair with a follow-through down candle or resistance context.

Common pitfalls

• No location context. A gravestone mid-range means little.
• Confusing with a shooting star. A ShootingStar has a small body; a gravestone's body is effectively zero (a doji).

References

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

See also

• DragonflyDoji — the bullish mirror.
• ShootingStar — small-bodied bearish cousin.
• Indicators-Overview — the full taxonomy.