Hi-Lo
Master the famous Hi-Lo card counting system with Protocol 21. The world's most popular balanced counting system, explained and trained with casino-grade drills for iOS and Android.
What is the Hi-Lo card counting system?
The Hi-Lo system assigns +1 to low cards (2-6), 0 to neutral cards (7-9), and -1 to high cards (10-Ace). It is the world's most popular balanced card counting system because it is easy to learn and provides a reliable edge over the house in any multi-deck blackjack game.
Card Values at a Glance
| Cards | Count Value | Category |
|---|---|---|
| 2, 3, 4, 5, 6 | +1 | Low |
| 7, 8, 9 | 0 | Neutral |
| 10, J, Q, K, A | -1 | High |
System Performance Metrics
These statistics define the mathematical capabilities of the Hi-Lo system. Higher is better for all three correlation metrics.
| Metric | Score |
|---|---|
| Betting Correlation (BC) | 0.97 |
| Playing Efficiency (PE) | 0.51 |
| Insurance Correlation (IC) | 0.76 |
| System Level | 1 (Level 1) |
History & Origins
The Hi-Lo system was developed by Stanford Wong in the 1960s and popularized by Peter Griffin's work in 'The Theory of Blackjack'. It was later refined by Edward Thorp. Today, Hi-Lo is used by the majority of professional card counters worldwide because its betting correlation of 0.97 is nearly optimal while remaining easy to execute at casino speeds.
Hi-Lo vs. Other Systems
Compared to more advanced systems like Omega II or Wong Halves, Hi-Lo sacrifices some playing efficiency (0.51 vs. 0.67) but eliminates the cognitive load that causes most counters to make critical mistakes under pressure. For the vast majority of advantage players, the net edge of a flawlessly executed Hi-Lo count will outperform a sloppily executed Omega II.
Train Hi-Lo with Protocol 21
Protocol 21 features dedicated Hi-Lo drill modes, speed training, casino noise simulation, and offline play with no scammy in-app coins. It is the only app that supports all 6 major counting systems.
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