On-Neck Pattern (CDLONNECK)

Summary

A two-candle on-neck pattern: a long black candle followed by a white candle that opens below the prior candle's low and closes right at that low. Bearish continuation signal. A hit is bearish (bearish continuation); the code does not verify the assumed prior downtrend.

Formula

Two candles. 1st: black (close<open) with long real body (realbody > BodyLong average). 2nd: white (close>=open); open < prior low; close within the Equal band of the prior low, i.e. (prior_low - EqualAvg) <= close2 <= (prior_low + EqualAvg).

Notes

The bearish-continuation reading assumes a prior downtrend, which is not verified.
Bulkowski's testing found the bearish continuation holds only 56% of the time, which he explicitly calls "near random." (thepatternsite.com)

Inputs

inOpen — Open price of each bar
inHigh — High price of each bar
inLow — Low price of each bar
inClose — Close price of each bar

Outputs

outInteger — -100 on a match, 0 otherwise. Only -100 is ever emitted (never +100); on-neck is always bearish

Output Values

Value	Meaning
-100	On-Neck pattern detected: bearish continuation
0	No pattern

Properties

Numerical Stability: Start-Independent


☐ Overlap Input
✅ Independent Y-Axis i
✅ Candlestick i
☐ Can Output NaN or ±Inf
☐ Identity at Period 1

Implementation

TA-Lib Definition: cdlonneck.c · cdlonneck.yaml

Native	File
C	`ta_CDLONNECK.c`
Rust	`cdlonneck.rs`
Java	`Core_CDLONNECK.java`

TA-Lib is also available for Python, R and more using a wrapper.

Aliases

On-Neck Pattern, On-Neck Line