What Casinos Do to Stop Blackjack Card Counters

Outside Casino Entrance, Poker Cards Spread Out
Card counting isn’t illegal, but it’s highly looked down upon by casinos. After all, skilled card counters can win big profits off of gambling establishments.

That said, casinos do everything in their power to stop card counters. The goal is to catch advantage players in the act and potentially ban them.

At the least, gambling establishments want to throw counters off their game and make them uncomfortable.

But what are the methods that casinos use to accomplish these goals? I’m going to discuss multiple techniques that they use to hamper card counters.

Feature Unfavorable Rules

Casinos were mostly unaware of card counting in blackjack up until the early 1960s. Edward Thorp changed this, though, with his 1961 book Beat The Dealer.

In this work, Thorp discussed how he used card counting to beat the casino and win profits. Since then, gambling venues have instated unfavorable rules to make counting less profitable.

Most games today now feature shoes with multiple decks. This is a change from Thorp’s days when most blackjack tables were the single deck variety.

Many tables also feature 6-to-5 natural blackjack payouts, rather than 3-to-2 payouts. This single change increases the house edge by 1.4%.

Specific tables also allow the dealer to hit a soft 17. This rule boosts the house edge by 0.2% because it helps dealers improve their soft hands.

Casinos also reshuffle the shoe frequently to prevent more deck penetration. Advantage players can’t have as much confidence in their count with less than 70% penetration.

Watch for Big Bet Spreads

Once an advantage player detects a positive account, they need to raise their bets to capitalize on the situation. This is especially true when there’s more penetration in the shoe.

Blackjack Table with Dealer, Cards, and Casino Chips

The distance between the table’s minimum wager and the player’s max bet during a favorable count is known as the “bet spread.”

Here’s how this works:

  • The table’s minimum bet is $5.
  • A player raises their wager to $75.
  • 75/5 = 15
  • Their spread is 1-15.

Ideally, card counters would be able to spread their wagers from 1-15 or higher. Many casinos are fully aware of this tactic.

Therefore, one of the first things that a pit boss looks for when identifying a counter is their bet spread. A player who suddenly goes from the minimum bet to 15x this size is a dead giveaway.

Some casinos are more lenient when regarding bet spreads. However, they all have their limits and will begin scrutinizing anybody who has a large spread.

Looking for Players Who Make Big Buy-ins

The best card counters only have around a 1% advantage. With such a small edge, they’ll have almost as many losing nights as winning evenings.

They need a large bankroll to counteract the ups and downs of card counting. That said, the best counters will buy into a game for thousands of dollars.

Such a move won’t draw much attention at a high-stakes table. But it does raise eyebrows at low-stakes tables, which offer the low minimum bets that help counters minimize losses in unfavorable situations.

Backing Off Counters

“Backing off” card counters refers to the measures that casinos use to get into advantage players’ heads.

For example, the pit boss may watch a particular player while they’re gambling. They’re not only trying to observe if the player is a counter, but also make them uncomfortable.

The pit boss may take this even further by coming over to the table and standing near the advantage gambler. They might pretend like they’re just stopping by to chat with the dealer, but they’re really trying to back off the potential counter.

Another thing that pit bosses do is ask the dealer to shuffle the shoe more frequently. This accomplishes two things:

  1. Reduces deck penetration.
  2. It lets the player know that the casino may be on to them.

Use a Continuous Shuffling Machine

A continuous shuffling machine (CSM) allows the dealer to return used cards to the shoe. This device keeps shuffling the cards, meaning there’s no interruption in play.

Casino Table with Cards and Continuous Shuffling Machine

CSMs make card counting virtually impossible because they minimize deck penetration. Adept counters will avoid these tables altogether.

Ban Wonging

Famed gambling author Stanford Wong popularized a technique known as back counting, or “wonging.” Back counting is the process of standing off to the side of a table and counting cards.

The goal is to determine when there’s a positive count and then sit to play at this point. The player can then began making big wagers right away.

Wonging has a distinct advantage over traditional card counting because players don’t have to sit in during unprofitable points. Instead, they immediately have an advantage when they begin playing.

The only problem is that almost every casino has banned wonging. Such games have signs that state “no mid-shoe entry.”

These signs refer to how one must wait until a shoe is reshuffled before they can sit down.

Watch for Spotters & Big Players

If you’ve seen the movie 21, you may be aware of how the “big player” concept works. It involves spotters spreading out to different tables and playing games at the minimum bet.

The spotter’s job is to count cards until they determine a favorable count. They’ll secretly signal the “big player” to come to the table.

As for the big player, they sit down to the table and immediately begin placing large bets. Given that the big player places large wagers right away, they merely look like a high roller.

This strategy allows a card counting team to better camouflage their efforts. As long as the spotters can discreetly signal the big player, then the team has a good chance of counting without being caught.

Another advantage is that the team can cover multiple tables while looking for positive counts. The big player, meanwhile, can pick up their chips and move to a different table than the one they’re at when the count goes cold.

Of course, even the most skilled card counting teams can attract the pit boss’ attention eventually. Their signals could be a dead giveaway, as can the big player moving from table to table.

Keep a Database of Advantage Players

For the past few decades, casinos have been keeping detailed records of blackjack players. Some even subscribe to third-party databases that collect information on advantage players.

Griffin Investigations is/was the best-known example of a third-party service. They gained fame for taking down the MIT Blackjack Team.

Database Files, Pile of Blackjack Cards

Griffin was later sued by James Grosjean, though, and went bankrupt as a result. But there are other agencies, such as Biometrica and Oregon Surveillance Network (OSN), that carry on this work.

Any player covered in these databases will have a difficult time finding a game. Casinos that identify them will undoubtedly ask such players to leave.

Watching for Unusual Strategy Plays

Skilled card counters sometimes make unusual plays from a strategy perspective. Based on their count, they know when to deviate from basic strategy to maximize their return.

Here are examples of “bad” plays that card counters make:

  • Splitting 10s.
  • Standing on 15 or 16.
  • Doubling down on a soft 19 or 20.

Dealers will often notify the pit boss if they see such plays. After all, most gamblers that play blackjack with real money are adept enough to avoid making these mistakes.

If a counter is good enough at camouflaging themselves, they may be able to get away with such decisions. But they’ll really need to convince the staff that they’re just a bad gambler, rather than a highly-skilled advantage player.

Putting RFID Chips in Cards

Casinos’ efforts to catch card counters have gone high-tech in recent years. Case in point, they now put RFID chips in cards.

Bloodhound and Protec 21 software, for example, uses these chips in cards to try and determine a player’s edge. RFID tech is also being put in chips to track wager sizes.


Knowing the many ways that casinos identify card counters is one step closer to not being caught.

Then again, merely knowing how casino staff members spot counters doesn’t guarantee anything. You need to take things further by using various measures to avoid detection.

Everything begins with scouting out casinos that are more lenient. Some venues start backing off suspected counters right away, while others wait for obvious cues before taking action.

You also need to have a good mind for what bet spreads you can get away with. Some casinos may briefly allow 1-15 spreads, while others will immediately become suspicious of 1-8 spreads.

Another crucial step is to pick the right tables. You’re unlikely to find any quality single-deck games where the pit boss won’t back off any suspected card counters.

But you at least want to find a table with 3:2 natural payouts. After all, you can’t make much, if any, money when counting at a table with 6:5 payouts.

Blending in is yet another essential aspect of card counting. You should spend time observing how regular players dress and act, then try emulating them while card counting.

Of course, first thing’s first: you need to master counting amid all of the casino distractions. Once you get this down, then you can start worrying about evading the casino’s watchful eye.