Contra D’Alembert
Overview
The mirror image of the classic D’Alembert: increase stake by 1 unit after a win, decrease by 1 unit after a loss. A positive progression that compounds winnings and shrinks during losing runs. Much safer than standard D’Alembert.
How It Works
- Start with 1 unit
- Win: Increase stake by 1 unit
- Loss: Decrease stake by 1 unit (never below 1)
- No profit target per se — just ride the waves
Example: 1 (Win) → 2 (Win) → 3 (Lose) → 2 (Win) → 3 (Lose) → 2 (Lose) → 1
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
base_unit |
number | 1 | Starting and minimum stake |
increment |
number | 1 | Units to change per result |
Risk Assessment
- Risk Level: Low
- Max Drawdown: Limited — stakes decrease during losses
- Recommended Bankroll: 30+ units
When to Use
- Your winners cluster in streaks
- You want the safety of decreasing stakes when cold
- You prefer positive progression psychology
When to Avoid
- Isolated winners (rarely build momentum)
- You want a specific profit target mechanic
Contra vs Standard D’Alembert
| Standard | Contra | |
|---|---|---|
| After win | Decrease | Increase |
| After loss | Increase | Decrease |
| Risk profile | Medium | Low |
| Philosophy | Chase losses | Ride winners |
Betfair Exchange Notes
- For lay Contra D’Alembert, decrease liability after losing lays, increase after winning lays
Related Plans
- D’Alembert — Standard (negative progression) version
- Paroli — More aggressive positive progression (doubling)
- Oscar’s Grind — Another conservative positive progression
Sources
- Plan mechanics: Classic betting system (public domain)
- Plan catalog reference: The Staking Machine — staking plan software with 50+ plans