The Uston Advanced Plus Minus Card Counting System

The Uston Advanced Plus-Minus card counting system is also sometimes just called the "Plus-Minus" system. It's a reasonably easy system to use, but it works better in games with fewer decks. The system takes its name from author and blackjack player Ken Uston, and it was presented for the first time in his book, Million Dollar Blackjack.

This page covers some of the basics behind card counting, although you'll find a more comprehensive treatment of that subject on our main counting cards page. It then goes into specifics of how this particular system works in practice.

How to Count Cards

Learning how to count cards using the Uston Advanced Plus-Minus system isn't too different from learning to count cards with any other system. You start with the basics, which is an understanding of WHY card counting works.

Counting cards works because the odds of winning change based on which cards are left in the deck. Unlike other casino games, like roulette, blackjack has a memory. Once a card is dealt, it can't be dealt to a player again until it's shuffled back into the pack.

In roulette, the same number can come up again and again. It doesn't disappear once it's been hit.

Why does the changing composition of the deck matter?

Think about where you win the most money in a blackjack game. It's when you're dealt a natural, right? (A natural is also called a "blackjack". It's a 10 and an ace, so it's a 2 card total of 21.) The hand pays off at 3 to 2. All other hands pay off at even odds in most blackjack games.

So if you bet $100 and get a natural, you win $150.

The odds of getting such a hand change based on how many high cards are left in the deck versus how many low cards are left in the deck.

If you think about it for a second, it's not hard to understand why having certain cards dealt would affect your possible outcome. Imagine a game where all the aces had already been dealt. Your probability of being dealt a natural drops to 0 in that case.

So it stands to reason that if you can estimate how many aces and 10s are in the deck versus how many low cards are left in the deck, you can get an idea of when you're more or less likely to be dealt a natural. If you raise the size of your bets when you're MORE likely to get a natural, and if you lower the size of your bets when you're LESS likely to get a natural, then you can increase your expected return to a point where you have an edge over the casino.

You don't have to memorize which cards have been dealt in order to do this, either. Instead, you assign certain values to the different cards, then keep a running count of those values. When a card has been dealt that improves your odds, you add a number to the running count. When one has been dealt that hurts your odds, you subtract a number.

Based on the count, you increase and decrease your bet sizes accordingly. You might also make certain changes to your basic strategy decisions based on the count.

How the Uston Advanced Plus Minus System Works

The Uston Advanced Plus Minus System is considered a single level counting system. That means that cards only have one value: + or – 1.

It's also considered a balanced counting system. This means that there are as many +1s in the deck as -1s, and if you count through the entire deck, you'll wind up with a running count of 0.

• In this system, every time you see an ace or a 10, you'll subtract 1 from your running count.
• Any time you see a 3, 4, 5, 6, or 7, you'll add 1 to your running count.

One of the ways to look at a card counting system is to think about how efficiently the system correlates to your changes in odds. One measure is "betting correlation". This is an estimate of how effective a particular system is in getting you an edge when you raise and lower your bets. According to QFIT, the betting correlation for this system is 0.95, making it VERY accurate in terms of helping you get an edge when raising the size of your bets.

Another metric is "playing efficiency". This is a measure of how well the count does at helping you adjust your basic strategy while playing. (Basic strategy is the mathematically correct way to play every hand.) The playing efficiency for this system is 0.55, which sounds awful when compared to the betting correlation of 0.95. But playing efficiencies in general are lower than betting correlations, across the board. 0.55 isn't great, but it's not terrible, either.

It's actually quite similar in details to another system, the Hi-Lo.

But there is one more step besides just tracking the running count. If you're playing in a game with multiple decks, you have to take into account the "dilution effect". Basically, the dealing of a single card has more of an effect on your bottom line when you're playing with one deck than if you're playing with 2 or 4 decks.

That's easy to understand, too, if you think about it. If you only have one deck, and all 4 aces have already been dealt, the odds of getting a blackjack are 0. But if you have 2 decks, and 4 aces have already been dealt, the odds of getting a blackjack are reduced, but they're not eliminated.

To adjust for this, card counters convert their running count into what's called a "true count". This is easier than it sounds. You just estimate how many decks are left in the shoe. Then you divide your running count by the number of decks to convert it into a true count. That's the number you use to determine your bet size.

In most card counting systems, you'll come up with a betting range, and you'll increase the size of your bets based on the true count.