Crab Pattern and Deep Crab

The Crab goes where other patterns fear to tread — the deepest exhaustion extremes.

Discovered by Scott Carney in 2000, the Crab is the most extreme of the standard harmonic patterns. Point D completes at the 1.618 extension of the XA leg, far beyond the origin X. This deep completion places the reversal zone in climactic territory, where exhaustion is greatest and reversals can be explosive.

The structure

A bullish Crab forms after a decline; a bearish Crab forms after a rally. The defining ratios:

• X to A — initial impulse leg.
• A to B — retraces 0.382 to 0.618 of XA (relatively shallow).
• B to C — extends 0.382 to 0.886 of AB.
• C to D — completes at 1.618 of XA (the signature level).

The key rule: D extends exactly 1.618 of XA, and the CD leg is typically a large 2.24, 2.618, or 3.618 of BC.

Ratio checklist

Leg	Required ratio
AB	0.382–0.618 of XA
BC	0.382–0.886 of AB
CD	2.24, 2.618, or 3.618 of BC
XD	1.618 of XA

Why the Crab reverses

The 1.618 extension of XA places D at the limit of where the prior leg can rationally extend. By then, trend-followers are exhausted, stops are clustered, and the move is over-extended. Reversals from Crab completions are frequently sharp.

The Deep Crab

A Deep Crab is a variant where point B retraces beyond 0.618 — up to 0.886 of XA — but the defining D completion remains at 1.618 of XA. The deeper B makes the entire structure more stretched, and the CD leg becomes extreme. Deep Crabs complete at true capitulation lows or euphoric highs and offer the largest reversal potential of the harmonic family.

Trading the Crab

Entry: wait for reversal confirmation at D. Because D is at an extreme, the reversal bar is usually obvious — a long-wick hammer or VSA stopping volume.

Stop: just beyond D. The stop is wide because D is far from X, so position sizing must be conservative.

Targets:

• Target 1: 0.382 retracement of CD.
• Target 2: 0.618 retracement of CD.
• Target 3: point A (full retracement to origin).

Bullish Crab example

1. Stock falls X=$100 to A=$80 (XA = $20).
2. Rallies to B=$87.64 (0.382 retracement).
3. Falls to C=$84.
4. Extends to D=$67.76 (1.618 of XA: 100 − 20×1.618 = 67.76).
5. Reversal bar at D — long, stop below $67.

Risk is wide, but a successful reversal can run back to $84–$90, producing a reward many times the risk.

Strengths and pitfalls

Strengths:

• Largest reversal potential of the standard harmonics.
• Completes at true exhaustion extremes.
• Mechanical, repeatable rules.

Pitfalls:

• Wide stop demands small position size.
• Price can overshoot 1.618 to 2.618 in extreme trends — invalidating the trade.
• Requires patience — Deep Crabs can take weeks to form.

Best context

Crabs shine at major higher-timeframe extremes: weekly support/resistance, round-number levels, and where momentum diverges from price. A Deep Crab at weekly support with daily RSI divergence is a flagship harmonic setup. Avoid trading Crabs in low-volatility ranges — they need extended conditions to complete meaningfully.

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Next: the Cypher pattern, a newer and increasingly popular harmonic structure.