The Knock Out Card Counting System

The Knock Out System, also known as the KO count, is one of the most popular methods for counting cards and for its simplicity, it is often preferred by recreational blackjack players. It is widely considered to be less accurate than other, more advanced methods. Still, it is good for estimating when the odds are good or bad.

The KO count was introduced in 1998 by electrical engineer and cryptographer Ken Fuchs and astrophysicist Olaf Vancura in their book Knock Out Blackjack – The Easiest Card Counting System Ever Devised. Coming from purely scientific backgrounds, the authors have researched and proved the efficiency of this method. Fuchs and Vancura based the KO count on an earlier, unrefined system for counting. Their version, devised scientifically, aims at allowing players to count cards without having to do complex mental arithmetic.

The simplicity of the method, however, comes at a price – it is not the most accurate, efficient, or profitable system for counting cards. The article below explains how the KO works, how it is applied in practice, and what weaknesses should be considered by blackjack players.

The Knock Out Card Counting System Fundamentals

Basics of the Knock Out System
How to Use the Knock Out System

Basics of the Knock Out System

All card counting systems assign certain point values to the cards in the deck and by keeping an accurate count during the game, players can determine whether the shoe is rich in favorable or unfavorable cards. In other words, whether there are more high than low cards still not played. The Knock Out System functions in the same manner but unlike conventional systems such as the Hi-Lo count, it can be described as an unbalanced counting system.

What makes it different is the uneven number of positive and negative value cards. Under the KO count, cards from 2 through 6 are counted as +1, while Aces, 10s, and face cards are assigned a point value of -1. In this system, 8s and 9s are worth 0, but 7s are also assigned a value of +1. This means that when we count using this method, we will eventually reach a running count of +4 per deck.

  • 2, 3, 4, 5, 6, 7 – +1
  • 8, 9 – 0
  • 10, J, Q, K, A – -1

This single-level system is extremely easy to learn because there is only one point value that must be memorized (+/-1). The idea behind the lack of balance, according to Vancura and Fuchs, is to eliminate the need to convert the running count into a true count. With this system, they claim, players simply keep a count as the cards appear on the table and do not have to worry about the total number of decks in use and how many of them are remaining in the dealing shoe.

How to Use the Knock Out System

The Knock Out System is easy to apply in real-life games without the need to practice it for days or weeks. Players simply add or subtract 1 from the initial count as different cards are being dealt on the table. By keeping the running count at all times – during and in between rounds, players will always know if the odds are against them or are, in fact, in their favor.

There is one important thing to note, however. Unlike most simple systems where the initial count starts at 0, things get more complicated here. Players start at the Initial Running Count (IRC), which varies depending on the number of decks in use. It is calculated with the formula – IRC = 4 – (4 x number of decks). If the game is played with only one deck of cards, we start with a standard IRC of 0 but if we play an 8-deck game, the IRC plunges to -28. Below, you can see the IRC for every type of blackjack that is currently offered:

  • 1 deck – IRC is 0
  • 2 decks – IRC is -4
  • 4 decks – IRC is -12
  • 6 decks – IRC is -20
  • 8 decks – IRC is -28

It is necessary to always start with the right IRC – it guarantees that when we count down to the last card in the shoe, we will end up with a final running count of +4. This may all sound a little bit challenging, especially to someone who has just started counting cards but the KO count is, indeed, very simple and easy to apply in a real-life game of blackjack.

To illustrate this, let’s take a 6-deck game for example – after the reshuffle, we start the count at -20. It is best to not yet sit on the table – alternatively, players can sit and place 1-unit bets. The cards appearing on the table are 5, 8, Ace, 9, Jack, 4, 8, 3, and 6 for a total count of +2. The running count will then be -18. Once it becomes a positive value (at least +2), players can increase their bet size to 2 or more units.

This is the most crucial moment in the game – when the odds shift in players’ favor. This When using the KO count in a single-deck game, we should wait for the running count to become +2 to raise our bets. When we play a double-deck game, however, we increase the bets when the running count is +1. This is called the “key count” or “pivot count” and it varies, depending on the number of decks used:

Number of decks IRC Key Count
1 deck 0 2
2 decks -4 1
6 decks -20 -4
8 decks -28 -6

There is one more thing players should change, except for adjusting their bet size, when using the Knock Out method. They can, and should according to the creators of the system, deviate from the standard strategy with regards to the Insurance side bet. The basic strategy says never to take Insurance but KO allows it under the perfect circumstances – only if the running count is +3 or greater.

Advantages and Disadvantages of the Knock Out System


Weighing in the pros and cons of the KO method, the first thing to consider is its simple structure. Since it is a single-level system and has no side count for the Aces - unlike many other systems, it is easy to apply in an actual game of blackjack. Before using it, however, players need to make sure they can quickly calculate the sum of all cards visible on the table. This takes a little practice at home – first with a single deck and then, with two and more decks simultaneously.

Compared to most systems for counting cards in blackjack, the Knock Out method seems plain and straightforward but it is not completely effortless. To use it properly, players should always know the accurate initial running count (IRC) for the type of game they are playing. Of course, they should also know the key count, which indicates that the shoe is favorable and the bets should be raised.

The Knock Out system is also very convenient to use because it eliminates the need for a true count estimation. Typically, converting the running count into a true count is a difficult and tricky process that requires determining the number of decks that remain in the shoe. With this method, players skip this step altogether and proceed to bet sizing.

Another weakness of this system is that it is less accurate and effective than some advanced systems for counting cards. The creators of the method have calculated that even when playing with perfect strategy and standard blackjack rules, players will not be able to eliminate the house edge with the KO count with a conservative betting spread of 1-2. This is true for 6 and 8-deck games, in particular.

Under the best conditions and with a more aggressive betting spread (1-10), blackjack players can achieve a mathematical advantage of up to 0.43% (in 8-deck games), 0.54% (6 decks), or 1.24% (single deck). More complex systems, however, can increase the player’s advantage to around 2%.

Learning the Knock Out system is a must for all blackjack players who are just starting to count cards with the hope to gain an advantage over the house. The system is suitable for all types of counters as it clearly shows the fundamental ideas of card counting. When used in combination with perfect strategy and a larger betting spread, the KO method could help serious players generate good profits in real blackjack games.

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