Introduction
The KO (Knock-Out) system, developed by Ken Fuchs and Olaf Vancura, is the simplest path to effective probability tracking. It’s nearly identical to Hi-Lo, with one elegant twist: the 7 is counted as +1 instead of 0. This single change makes the system unbalanced, which eliminates the need for true count conversion entirely.
If you’ve been struggling with the division step in Hi-Lo’s true count calculation, KO might be the system for you.
Card Values
| Card | KO Value | Hi-Lo Value | Difference |
|---|---|---|---|
| 2 | +1 | +1 | Same |
| 3 | +1 | +1 | Same |
| 4 | +1 | +1 | Same |
| 5 | +1 | +1 | Same |
| 6 | +1 | +1 | Same |
| 7 | +1 | 0 | Changed |
| 8 | 0 | 0 | Same |
| 9 | 0 | 0 | Same |
| 10 | -1 | -1 | Same |
| J | -1 | -1 | Same |
| Q | -1 | -1 | Same |
| K | -1 | -1 | Same |
| A | -1 | -1 | Same |
Only one card changes: the 7 moves from neutral to +1. Everything else is identical to Hi-Lo.
Why Unbalanced Works
In a balanced system like Hi-Lo, a full 52-card deck sums to 0. In KO, a full deck sums to +4 (because there are four 7s, each now worth +1).
This means if you count through an entire single deck using KO, you’ll end at +4 instead of 0. For a 6-deck shoe: 6 × 4 = +24.
The key insight: Because the system is unbalanced, the running count itself carries information about deck penetration. You don’t need to divide by remaining decks — the running count already factors in how deep into the shoe you are.
The Initial Running Count (IRC)
Instead of starting at 0, KO starts at a negative number called the Initial Running Count. This is calculated as:
IRC = -4 × (number of decks - 1)
| Decks | IRC |
|---|---|
| 1 | 0 |
| 2 | -4 |
| 6 | -20 |
| 8 | -28 |
For a standard 6-deck shoe, you start counting at -20.
The Key Count and Pivot
KO uses two important thresholds instead of true count ranges:
Key Count (0): When the running count reaches 0, you’re at approximately break-even. This is the point where the player’s edge starts turning positive.
Pivot (+4): When the running count reaches +4, you have a significant advantage — roughly equivalent to a true count of +2 in Hi-Lo.
For betting:
- Running count < 0 → Minimum bet
- Running count 0 to +3 → Moderate increase
- Running count ≥ +4 → Maximum bet
Worked Example: 6-Deck Shoe
Starting IRC: -20
| # | Card | Value | Running Count |
|---|---|---|---|
| 1 | 5♣ | +1 | -19 |
| 2 | K♦ | -1 | -20 |
| 3 | 7♠ | +1 | -19 |
| 4 | 3♥ | +1 | -18 |
| 5 | 2♠ | +1 | -17 |
| 6 | 6♣ | +1 | -16 |
| 7 | A♠ | -1 | -17 |
| 8 | 4♦ | +1 | -16 |
| 9 | 8♥ | 0 | -16 |
| 10 | 5♦ | +1 | -15 |
After 10 cards, the count is -15. Still negative, so minimum bets. As you go deeper and more low cards are dealt, the count climbs toward 0 and beyond.
Practice Exercises
Count these sequences using KO (start at 0 for single-deck):
Sequence 1: 7♠, K♥, 3♦, 8♠, 5♣
Answer
(+1) + (-1) + (+1) + (0) + (+1) = +2
Note: In Hi-Lo this would be +1 (the 7 would be 0).
Sequence 2: 2♥, 7♣, 7♦, A♠, 10♣, 9♦, 4♣
Answer
(+1) + (+1) + (+1) + (-1) + (-1) + (0) + (+1) = +2
In Hi-Lo: (+1) + (0) + (0) + (-1) + (-1) + (0) + (+1) = 0. The two 7s make a significant difference.
KO vs Hi-Lo: When to Choose KO
Choose KO if:
- You find true count division difficult or slow
- You want a simpler mental process
- You’re playing in conditions where speed matters more than precision
Stick with Hi-Lo if:
- You’re comfortable with the true count calculation
- You want the most widely documented system
- You plan to use index plays (playing deviations based on specific true counts)
Performance comparison:
- KO Betting Correlation: 0.98 (slightly higher than Hi-Lo’s 0.97)
- KO Playing Efficiency: 0.55 (slightly higher than Hi-Lo’s 0.51)
- Both are Level 1 systems — same mental difficulty for card recognition
Key Takeaways
- KO is identical to Hi-Lo except 7 = +1 instead of 0
- The system is unbalanced — a full deck sums to +4 per deck
- Start with a negative IRC and count up toward 0 and beyond
- No true count conversion needed — use the running count directly
- The pivot point (+4) signals a significant player advantage
- KO slightly outperforms Hi-Lo in both BC and PE
Next Steps
Explore Hi-Opt I if you want a system optimized for playing decisions, or return to the counting systems comparison for an overview. Practice KO in the 21 Sharp app by selecting it in the system picker.