Heikin-Ashi

"Average bar" — a Japanese candle-smoothing transform that emphasises trend continuity. Each Heikin-Ashi candle's OHLC is derived from the real candle plus the previous Heikin-Ashi candle, so consecutive same-colour HA bars confirm a trend more cleanly than raw candles. Streaming O(1) state machine — one HA candle per real candle, starting from the very first bar.

Quick reference

Item	Value
Family	Ichimoku & Charts
Input type	Candle
Output type	HeikinAshiOutput { open, high, low, close: f64 }
Output range	unbounded (price-units)
Default parameters	none — HeikinAshi::new()
Warmup period	1
Interpretation	Smoothed candle series; same-colour HA streaks confirm trend

Formula

ha_close_t = (open_t + high_t + low_t + close_t) / 4

ha_open_t  = (ha_open_{t-1} + ha_close_{t-1}) / 2    (recursive)
ha_open_1  = (open_1 + close_1) / 2                    (seed for first bar)

ha_high_t  = max(high_t, ha_open_t, ha_close_t)
ha_low_t   = min(low_t,  ha_open_t, ha_close_t)

See crates/wickra-core/src/indicators/heikin_ashi.rs. The transform is purely local except for ha_open, which depends on the previous HA candle.

Parameters

None — HeikinAshi::new() takes no arguments.

Inputs / Outputs

Indicator<Input = Candle, Output = HeikinAshiOutput> with four fields (open, high, low, close).

• Python. HeikinAshi().batch(open, high, low, close) returns an (n, 4) float64 array with columns [open, high, low, close].
• Node. Flat number[] of length n * 4; streaming update(candle) returns { open, high, low, close } | null (only null on a non-finite candle, never on first bar).

Warmup

warmup_period() == 1. The first input emits a Heikin-Ashi candle seeded with ha_open_1 = (open + close) / 2.

Edge cases

• First bar seeding. ha_open for bar 1 uses the seed formula, not the recursion. Subsequent bars use the recursion.
• Constant input. All four HA fields converge to the constant (the average of identical values is the same value).
• Strict trend confirmation. When ha_open > ha_close for many consecutive bars, the HA candle bodies are all bearish (red) — a continuous "no-wick on top" sequence is the canonical HA strong-downtrend visual.
• Reset. Clears the previous-HA cache.

Examples

Rust

use wickra::{BatchExt, Candle, HeikinAshi, Indicator};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let candles: Vec<Candle> = (0..10).map(|i| {
        let b = 100.0 + f64::from(i);
        Candle::new(b, b + 1.0, b - 1.0, b + 0.5, 1.0, i as i64).unwrap()
    }).collect();
    let mut ha = HeikinAshi::new();
    let out = ha.batch(&candles);
    if let Some(o) = out[5] {
        println!("HA row 5: open={}  close={}", o.open, o.close);
    }
    Ok(())
}

Python

import numpy as np
import wickra as ta

n = 10
base = 100 + np.arange(n, dtype=float)
o = base
h = base + 1
l = base - 1
c = base + 0.5

ha = ta.HeikinAshi()
out = ha.batch(o, h, l, c)
print('shape:', out.shape)  # (10, 4)
print('row 5:', out[5])     # [ha_open, ha_high, ha_low, ha_close]

Node

const wickra = require('wickra');
const ha = new wickra.HeikinAshi();
const n = 10;
const base = Array.from({ length: n }, (_, i) => 100 + i);
const flat = ha.batch(base, base.map(b => b + 1), base.map(b => b - 1), base.map(b => b + 0.5));
console.log('row 5 ha_open :', flat[5 * 4]);
console.log('row 5 ha_close:', flat[5 * 4 + 3]);

Streaming

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

let mut ha = HeikinAshi::new();
let candle_stream: Vec<Candle> = Vec::new(); // your live OHLCV feed
for bar in candle_stream {
    let o = ha.update(bar).unwrap();
    let bullish = o.close > o.open;
    // Use HA candle colour as trend confirmation
}

Interpretation

• Trend smoothing. Consecutive same-colour HA candles confirm a trend; a HA candle with a small body and long wicks signals potential reversal.
• No-wick HA candles. A bullish HA candle with no lower wick (ha_low == ha_open) means the bar's true low was inside the HA body — a strong-trend visual.
• Vs raw candles. HA hides individual-bar noise; great for reading regimes at a glance. But because HA candles aren't actual prices, any level read off HA (e.g. "support at HA low") will not match real-price stops.

Common pitfalls

• Trading HA levels as real prices. HA candles are smoothed averages — ha_high is not necessarily a touched price. Stop orders set at HA levels will be wrong.
• Confusing HA candles with real candles. Many beginners apply pattern-recognition (e.g. doji, hammer) to HA candles. These patterns were developed on raw candles; their statistical edge does not transfer to HA.
• Multi-timeframe surprises. HA on a 1-min chart aggregated to 5-min HA is not equivalent to HA on 5-min raw candles. HA is order-dependent.

References

• Steve Nison, Beyond Candlesticks (1994) — covers Heikin-Ashi among Japanese charting variants.
• Various Japanese-trading practitioner texts (Heikin-Ashi was popularised in Japan long before its Western adoption).

See also

• Ichimoku — companion Japanese-charting system.
• Doji, Hammer, Engulfing — candlestick patterns (use on raw candles, not HA).
• Indicators-Overview — full taxonomy.