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Which card counting system is best?
Hi-Lo, for almost everyone. It is a balanced level-1 count with a betting correlation of 0.97, its strategy indices are the ones every book and trainer publishes, and it is what professional teams use. Higher-level counts add a few hundredths of a percent of edge and cost speed and errors, which is where real money is lost.
Published correlations (betting / playing / insurance): Hi-Lo 0.97 / 0.51 / 0.76; KO 0.98 / 0.55 / 0.78; Hi-Opt II 0.91 / 0.67 / 0.91; Wong Halves 0.99 / 0.56 / 0.72.
The common systems
The tag of each card, and the published correlations of each system.
| System | Level | Balanced | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 J Q K | A | Betting | Playing | Insurance |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Hi-Lo | 1 | Yes | +1 | +1 | +1 | +1 | +1 | 0 | 0 | 0 | −1 | −1 | 0.97 | 0.51 | 0.76 |
| KO (Knock-Out) | 1 | No | +1 | +1 | +1 | +1 | +1 | +1 | 0 | 0 | −1 | −1 | 0.98 | 0.55 | 0.78 |
| Hi-Opt I | 1 | Yes | 0 | +1 | +1 | +1 | +1 | 0 | 0 | 0 | −1 | 0 | 0.88 | 0.61 | 0.85 |
| Hi-Opt II | 2 | Yes | +1 | +1 | +2 | +2 | +1 | +1 | 0 | 0 | −2 | 0 | 0.91 | 0.67 | 0.91 |
| Omega II | 2 | Yes | +1 | +1 | +2 | +2 | +2 | +1 | 0 | −1 | −2 | 0 | 0.92 | 0.67 | 0.85 |
| Zen Count | 2 | Yes | +1 | +1 | +2 | +2 | +2 | +1 | 0 | 0 | −2 | −1 | 0.96 | 0.63 | 0.85 |
| Wong Halves | 3 | Yes | +0.5 | +1 | +1 | +1.5 | +1 | +0.5 | 0 | −0.5 | −1 | −1 | 0.99 | 0.56 | 0.72 |
Correlations as published by Don Schlesinger (Blackjack Attack) and Stanford Wong (Professional Blackjack); the tags are the systems’ own. Wong Halves is usually counted doubled at the table. The deck countdown on the card counting page drills any of them.
Why
Three numbers describe a system. Betting correlation says how well the count predicts the player’s edge, which is what the bets follow: the source of most of the profit. Playing efficiency says how well it predicts strategy changes, which matter more in single and double deck. Insurance correlation says how well it calls the insurance bet. Hi-Lo scores high where it counts, bets, and its weakness in playing efficiency is worth little in a six-deck shoe. KO is the choice for players who do not want to convert to a true count: it is unbalanced, so the running count alone drives the bets.