What is Deck Penetration in Blackjack And Why Is It Important?

Casinos used a “shoe” of cards in blackjack, which is comprised of multiple decks. The number of decks varies and is in itself an important factor for card counters. A lower number of decks is considered favourable as it makes it easier to count cards.

When only a single deck is used, players who card count can easily gain an edge. This is why casinos use multiple shuffled together, usually anywhere between two and eight decks of cards.

These cards have to be cut and reshuffled at some point, whether that be early on or with only a few cards remaining. Deck penetration refers to the proportion of cards that are dealt out before the shoe is reshuffled by the dealer. 

This is denoted by the cut card, which is placed in the shoe. With keen observation, players can see where the cut card is placed to understand the depth of the deck penetration. The deeper the deck penetration, the more favourable the game is for card counting.

Why is deck penetration important?

The truth is, deck penetration really isn’t important unless you are card counting. It’s also only relevant for live blackjack. When you play blackjack online, card counting is a strategy that can be utilized, aside from, perhaps, in the live studio dealer games, which are widely available on major platforms. 

For those who are card counting, a deeper deck penetration is much better. In fact, it’s arguably more crucial than picking a blackjack game with a particular set of rules. 

For card counters, a deeper deck penetration will allow you to get a clearer picture of the true count and to realize your advantage for longer. 

For example, let’s say a shoe of two decks is shuffled when around 50 percent of cards are dealt. This means you will only see half of the cards and so your count is less accurate. Lots of the cards are behind the cut card and so it’s also impossible to know whether you will even see the high cards that you are waiting for. 

Now, let’s say a two-deck shoe is shuffled at around 80 percent penetration, which is a much more favourable depth. In this case, you will see a greater proportion of all the possible cards, which makes your true count more accurate. You’ll also be able to take advantage of a positive count for longer, as there will be more hands dealt before the deck is reset. 

To summarize, here’s how deeper deck penetration provides an advantage for card counting in blackjack:

• More information – You can see a greater percentage of the deck, which makes your true count more accurate.

• Utilize your advantage – If you have a high positive count, you can take advantage of it for longer knowing that more hands will be played before the deck is shuffled. 

Why do casinos allow a deep deck penetration? 

Casinos will often have a similar deck penetration running at all times. Of course, it will vary slightly, but often deck penetration, or how often the deck is reshuffled, is part of the training and company policy. 

Given that deeper deck penetration is an advantage for card counting, you would think that casinos would simply cut the decks very shallow to prevent players from gaining an edge. However, this is not the case. If anything, deck penetration has reportedly improved in recent years. 

This reason for this is simple. Shuffling decks of cards takes time. And time is money. 

Every time a dealer shuffles the decks, that’s a minute or two of time that bets are not being made. That doesn’t seem like a lot, but across tens or hundreds of tables running 24/7, it all adds up. Customers also tend to show dissatisfaction when the flow of the game is constantly interrupted by the cards being shuffled.

Casinos don’t want to lose money by having dealers shuffle too often. They have to find the balance and this often means having reasonably deep deck penetration. Instead, they rely on using other means, such as surveillance systems, to catch card counters. 

In any case, the depth of deck penetration in a blackjack game will vary across different establishments and even across dealers in the same casino. If you’re counting cards, it pays to find the right game.