Blackjack Deck Penetration Guide | LeoVegas

Blackjack Deck Penetration Guide

Blackjack deck penetration focuses on how deeply the dealer places the shuffle card in the shoe, or in other words, where the deck is cut. Traditionally, key factors in selecting a blackjack table have revolved around when the dealer stands and the blackjack payout odds. However, seasoned players now emphasize the significance of higher deck penetration as equally, if not more, crucial in this decision.

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Where the shoe is cut or needs to be shuffled determines what percentage of the total cards will never be seen and are out of the game. Consequently, both blackjack players looking to employ basic strategy and seasoned card counters are disadvantaged by shallow deck penetration.

Here, we’ll delve into this once seemingly innocuous part of playing blackjack. Read on to discover more about deck penetration in blackjack, how to calculate it, and the role it plays in card counting.


What is Deck Penetration in Blackjack?

Deck penetration in blackjack is a term that refers to the number of available cards that will be played before a reshuffle. Where the shuffle point is, or rather, the percentage of deck penetration, will influence the round and may dissuade some experienced players from sitting at certain tables.

Understanding Deck Penetration

The basic premise of blackjack deck penetration is for the casino to uphold some house edge. Blackjack is unique among casino table games in that, in perfect conditions, the right plays can be made to reduce the house edge to an incredibly low value.

Cutting the deck and reshuffling before the shoe is finished claws back some house edge as skilled players won’t be able to account for cards that don’t come into play. So for players, it’s an element that will impact the ideas of variance between hands.

When players talk about blackjack deck penetration, it’s invariably as a percentage. This percentage, be it 80%, 65%, or 30%, refers to the percentage of the total cards in the shoe that will be played through. A higher deck penetration is better as you’ll play through more cards.

Importance of Deck Penetration in Blackjack

Deck penetration in blackjack is very important because it indicates how many cards are cut out of the game. While shuffles are completely random, more cards offer more variance and a closer mark to the distribution that you know is possible from only one deck, two, four, or six decks in play.

How Deck Penetration Affects Gameplay

Quite simply, higher deck penetration in blackjack reduces your chances of getting the cards that you need to make stronger hands and close in on 21. While basic strategy isn’t hindered in practice, it is in execution simply by virtue of unknown cards being left out from each round.

Factors Influencing Deck Penetration

Blackjack deck penetration isn’t standardized. At each table, it’s worth knowing where the shuffle point is and the percentage of cards lost to the cut for each playthrough.

Number of Decks Used

When calculating blackjack deck penetration, usually, it’s as simple as working out the remaining percentage after one deck or two decks’ worth of cards get cut. However, two decks cut from a four-deck game is very different from two being cut from an eight-deck game. The golden rule is that fewer decks and greater deck penetration provide larger variance and, thus, a greater advantage for the player.

Shuffle Point

The shuffle point indicates when the whole shoe will be shuffled, or a new shoe will be brought in the case of some live casino tables, to reset the deck penetration. It’s essentially the marker for where deck penetration ends. This is important for those who apply more advanced strategies, as it indicates how many hands you have before you need to restart the strategy.

Casino Policies

Casinos instigate their own policies on deck penetration. As a rule, casinos with a policy of less than 70% deck penetration are unfavourable for players, while anything above 80% is considered to be good deck penetration.

Calculating Deck Penetration

To calculate deck penetration in blackjack games, you look at the remaining cards left in play. In a six deck game, it’s not uncommon for two decks to be cut. This leaves four of the six decks still in play for a deck penetration of 66.66%. Two decks being cut from a four-deck blackjack game, though, would only leave 50% deck penetration.

Methods for Estimating Deck Penetration

Using the method above to directly work out blackjack deck penetration is the ideal way, but sometimes you’re not made privy to the exact shuffle point. In situations like this, you can usually find out how many decks are in play. At the start of a round, gauge where the middle of the shoe is, and from there, you want your cut to come at least close to halfway between that mark and the base of the shoe. This would offer around 75% or the equivalent of two decks cut from an eight-deck shoe or 1.5 decks out of a six-deck game.

Tools and Techniques

The only tool that you may need to work out blackjack deck penetration is a calculator, and the technique is just working out a percentage. For eight deck games of blackjack, with eight being the whole, each deck is worth 12.5% of the whole shoe. So, two decks cut is a 25% cut leaving 75% deck penetration.

The Roles of Deck Penetration in Card Counting

The size of the deck penetration in any game of blackjack is a huge factor in card counting. Many seasoned counters say that you can’t beat a game with 60% or more deck penetration. With fewer decks in play, like in double-deck blackjack, even though the inherent house edge is lower, high penetration will hinder strategies.

How Deck Penetration Impacts Card Counting

Card counting is all about knowing what’s gone from the shoe to work out the probability of the cards you need to see next. The lower the deck penetration, the more cards will go unknown and ultimately, this will lead to less variance.

Variance is crucial for card counters, especially in identifying windows of high advantage based on a running true count. This count reflects the ratio of low, neutral, or high cards that have been dealt. Armed with this knowledge, counters can hone in on opportunities when there are expected to be significantly more high cards remaining, as a greater proportion of low cards have already been played.

Adjusting Strategies Based on Penetration

In terms of the Hi-Lo count strategy, true count needs to factor in deck penetration. This will come in the form of the true count always being divided by the number of decks left at any given time. With lower deck penetration, this dividing number is always higher, cutting the possible windows of advantage. Higher deck penetration means that, as more cards are dealt, the calculated true count will become more accurate.

Blackjack Deck Penetration FAQs

What is deck penetration?

Deck penetration indicates the number of total cards in the shoe that remains above the dealer’s shuffle point. Regardless of the number of decks, blackjack players want higher deck penetration to have the most advantage against the house.

How does deck penetration affect gameplay?

Even for casual blackjack players, deck penetration will greatly affect gameplay. A high deck cut significantly cuts off the number of cards that can be dealt and increases the potential variance due to the number of cards left out of determination. With a rudimentary read, in a double-deck blackjack game, if the penetration is only 50%, you’re far from guaranteed to get four aces before the decks are shuffled. So, you don’t have to be counting cards for deck penetration to impact the gameplay and your experience.

Can deck penetration be manipulated?

Deck penetration can’t be manipulated directly by any player because the shuffle card is placed at a predetermined depth in the shoe. However, the method of ‘Wonging’ – which is often banned at land-based casinos by not allowing anyone to sit after the first hand is dealt – can help you jump in at a point when the determined true count is advantageous. Still, this is a form of card counting and isn’t permitted at many casinos either.

Why do blackjack dealers cut the deck?

Blackjack dealers cut the deck to further reduce the efficiency of any strategy being deployed by skilled players. By cutting the deck, there’s more uncertainty to any application of basic strategy or card counting. The more shallow the deck penetration, the greater the disadvantage to the players.

Are blackjack odds better with more decks?

Blackjack odds, in reference to a player’s likelihood of winning when applying basic strategy, are always better with fewer decks. Single-deck blackjack offers the best odds for the player - but it’s this very reason that may make a single deck blackjack table tricky to find! The house edge increases with each added deck, so you’re most likely to run into four, six, and eight deck shoes.

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