Many Hollywood movies and TV shows have been dedicated to the ‘art’ of card counting in casinos, which is a high stakes way for players to gain an advantage on the house. The sharp blackjack-playing protagonist will track the cards quietly as they are dealt, keeping a running count in their head and raising their bets when the deck turns in their favour. This requires math, discipline and timing. At a single-deck table, this kind of counting was easier to pull off.
But these days, both land-based and online casinos have shifted away from single deck blackjack in favour of multi-deck games. On some licensed platforms, you can find well over a hundred live blackjack tables. Almost all of these use six to eight decks rather than just one.
Because of this, many players assume that single-deck blackjack has disappeared from the modern casino scene. It hasn’t disappeared completely, but it’s become far less common — and card counting is only one reason why.
The Birth of Blackjack
Nowadays a large part of gambling has moved online. It’s possible to play both for real money or for free, in a demo mode, for example at https://legalbet.uk/free-casino-games/, which is an expertly compiled selection of popular free casino games.
But the roots of casino games go back centuries, and blackjack is no exception – its origin is traced to early European “Twenty-One” games played long before modern casinos existed. Back then, there were no fancy deck-shuffling machines, so single-deck blackjack – with the cards shuffled and dealt by a croupier – was the norm.
When blackjack emerged from backstreet gambling dens and into Las Vegas casinos in the first half of the twentieth century, intelligent types realised that players could gain an edge on the house by learning to count cards – or ‘card tracking’, as famed mathematician and author Edward O. Thorp termed it.
It was a technique that worked best in single deck blackjack, where the math was simpler and the swing in odds was more noticeable.
When Thorp published his game-changing book ‘Beat the Dealer’ in 1962, it opened the eyes of casino floor managers. They suspected that card counting had been going on for years, but Thorp – providing a step-by-step guide for even the average Joe or Jane to track cards – confirmed as much.
They were unable to stop card counting entirely, but certainly became more aware of the technique and those using it at the table. More and more players, under suspicion from security via their ‘eye in the sky’, would be persuaded that it would be in their best interests to leave the casino and never return.
A New Era
By the start of the 21st century, it was all-change. The digital revolution saw the rise of online casinos, which offered a range of blackjack variants. On most RNG tables, where there is no dealer, the cards are effectively reshuffled at the end of each round, so card counting does not carry over.
And while Edward O. Thorp has changed the game in favour of the players, Shuffle Master would hand the advantage back to land-based casinos with their latest innovation.
Shuffle Master’s Answer: The Continuous Shuffle Machine
The King was a continuous shuffle machine; the first of its kind to be produced on a mass scale. Dealers would place the deck of cards into the machine, which would then produce a random shuffle – creating a new order each time. Card counting was all but eliminated overnight.
Why Multi-Deck Blackjack Took Over
That saw a shift in popularity from single deck blackjack to more complex multi-deck games. In practice, most modern live and online blackjack tables use six to eight decks.
Why? For players, variety and unpredictability are introduced into the equation with each new deck – even though the card ratios stay the same, and a natural blackjack actually becomes slightly less likely as more decks are added.
Multi-deck games tend to be faster paced, thanks to the presence of a continuous shuffling machine, while each player’s decision-making process tends to be streamlined too – basic strategy stays consistent, but counting and tracking the shoe gets harder once you’re dealing with six or eight decks.
Where the House Pulls Ahead
Even if some players prefer the faster pace and the feel of a deeper shoe, it’s the house that gains the biggest edge from multi-deck blackjack. The probability of landing a natural blackjack actually decreases when more decks are added – from 4.83% to 4.75%, where eight decks are used.
This drop-off may seem marginal in percentage terms, but when you consider that millions of hands are played in the average casino each year, it makes a significant difference to their financial bottom line.
In pure numerical terms, the house edge of single deck blackjack is around 0.17%. In multi-deck games with eight decks used, that edge climbs to around 0.65%.
When you put it like that, it’s easy to see why casinos were so keen to introduce multi-deck blackjack. Single-deck tables also slow the game down, since they need more frequent shuffles, and they make advantage play easier to target, which is why many casinos avoid them, or offer them with weaker rules like 6:5 payouts on naturals.