KO (Knock-Out)

What is the KO (Knock-Out) card counting system?

The KO system is an unbalanced counting system that assigns +1 to cards 2-7 and -1 to 10-Ace. Because it counts 7s as +1 (unlike Hi-Lo), the count does not return to zero at the end of a shoe, eliminating the need for true count conversion. This makes KO significantly easier to execute in live casino conditions.

Card Values at a Glance

System Performance Metrics

These statistics define the mathematical capabilities of the KO (Knock-Out) system. Higher is better for all three correlation metrics.

History & Origins

KO was developed by Olaf Vancura and Ken Fuchs and published in their 1998 book 'Knock-Out Blackjack'. Designed as a response to the complexity of true count conversion, it was specifically engineered to be used in 6 and 8 deck games where the casino advantage is hardest to overcome. Its unbalanced starting point (which changes based on the number of decks) is its primary innovation.

KO (Knock-Out) vs. Other Systems

Unlike Hi-Lo, KO requires a deck-specific 'Initial Running Count' (IRC). For a 6-deck game, the IRC is -20. For a single deck, it is 0. Since the count is unbalanced, it drifts positive as the shoe progresses, naturally indicating when the deck is advantageous without any division. Counters who are comfortable with true count conversion may find Hi-Lo or Zen Count provide a higher long-run edge, but for players who want the simplest path to a positive EV, KO is the clear choice.