Card Counting Systems Compared
Hi-Lo, KO, Zen and the advanced counts - how they differ, and which one you should actually learn.
What is the best card counting system?
For almost everyone, Hi-Lo is the best card counting system. It is a simple, balanced, level-one count that captures most of the available edge. Advanced systems like Hi-Opt II, Omega II and the Zen Count add a little accuracy but a lot of difficulty, so most professionals stick with Hi-Lo.
Source: Griffin - The Theory of Blackjack, Schlesinger - Blackjack Attack
Every card counting system does the same job - estimate the ratio of high cards to low cards left in the shoe - but they trade simplicity for accuracy in different amounts. The trap beginners fall into is assuming a harder system means more money. Usually it does not. Here is how the major counts compare, and how to pick the right one.
How counting systems differ
Three things separate one system from another:
- Level - how many different values a card can take. Level 1 uses only +1, 0 and -1; higher levels add +2 and -2 for sharper accuracy.
- Balanced or unbalanced - whether the count nets to zero over a full deck (balanced) or is offset so you can skip the true-count conversion (unbalanced).
- Side counts - whether you track an extra card, usually the ace, on the side for better betting decisions.
The systems at a glance
| System | Level | Type | Difficulty | Best for |
|---|---|---|---|---|
| Hi-Lo | 1 | Balanced | Easy | Everyone - the default first count |
| KO (Knockout) | 1 | Unbalanced | Easy | Skipping true-count division |
| Red 7 | 1 | Unbalanced | Easy | A simple step up from KO |
| Hi-Opt I | 1 | Balanced | Medium | Playing accuracy with an ace side-count |
| Zen Count | 2 | Balanced | Medium | More power, moderate effort |
| Hi-Opt II | 2 | Balanced | Hard | Maximum playing accuracy |
| Omega II | 2 | Balanced | Hard | Advanced, serious players |
The systems, one by one
Hi-Lo is the world standard - low cards (2-6) are +1, high cards (10-A) are -1, and 7-9 are neutral. KO (Knockout) is Hi-Lo with the 7 counted as +1, which makes it unbalanced so you can bet without converting to a true count. Red 7 sits between them, counting only the red sevens. Hi-Opt I and II refine the values for better playing accuracy and usually pair with an ace side count. The Zen Count and Omega II are level-two systems that squeeze out a little more edge for players willing to juggle +2 and -2 values at speed.
Balanced vs unbalanced counts
A balanced count like Hi-Lo returns to zero if you count down an entire deck, which is why it needs the extra step of dividing by the decks remaining to get a true count. An unbalanced count like KO is deliberately offset so a high running count already signals an advantage - no division required. You trade a sliver of precision for a simpler workload, which for many casual players is a good deal.
Which system should you learn?
Learn Hi-Lo. It is the best balance of power and simplicity, it is the most documented system in the world, and the skills transfer if you ever move up. If the true-count division genuinely trips you up, KO is a fine unbalanced alternative. Save the level-two systems for when Hi-Lo is completely effortless and you are chasing the last fraction of a percent. Start with how to count cards and build from there.