Blackjack Double-Down-Card Switch
This switch involves a secret signal from the player and a maneuver by the dealer. The purpose of this switch is to steal money from the casino during a double down, in single-deck blackjack.
Following is a brief description of the double down procedure, for those unfamiliar with single-deck blackjack:
In single-deck casino blackjack, a player is generally allowed to double down on totals of 9, 10, and 11. To double down means to increase the bet by an amount equal to the amount of the initial bet. When a player catches an 11, it is commended to double down because the odds are high that he/she will end up with 21 by catching a 10-value card (because any full deck has sixteen 10-value cards: the 10s, Js, Qs, Ks). When doubling down on 11, the odds are further favorable because the player may also end up catching a 9-card, bringing his/her total up to 20. However, when a player does decide to double down, he/she is only allowed to receive one card. This card is called the double-down-card.
The action on this video has been reduced down to the necessary maneuvers. In a real game other active players would be present at the table, and the switch would happen after the dealer has played out his/her hand; and only if the dealer didn't happen to bust. Below is a description of the full strategy as would be done in a real game, with other active players seated at the table.
The player receives two cards. In this case he got a total of 11 (6C, 5D). The proper way to double down in single deck blackjack is to toss the hand forward and place an amount equal to the initial bet next to the wager; which is exactly what our player does. The dealer then deals a double-down-card. This is the first opportunity for the dealer to cheat. At this stage, the dealer will see the player's total and therefore will know what the player needs. If he sees a 9-card, or a 10-card on top, he will simply deal. If he sees a low-value card he may second deal to avoid dealing the unwanted card and get a second chance at catching a desirable one.
Next the player checks his double-down-card and see that it is an unwanted one. Since it is an unwanted card he places it back under the bet sideways. In our case this is the signal that calls for a switch. The player may even indicate the value of the card by placing a stack of un played chips in a certain way (not shown in this video), thus indicating that the double-down-card is, in this case, a 2-card.
The dealer will now have several opportunities to isolate a better card. This can be done by second dealing, while delivering hit-cards to other active players, or while playing his hand. Since the purpose of this strategy is to make the player win, the dealer may even deliberately bust by skipping favorable cards when playing his hand. If the dealer happens to bust naturally, the player wins; if the dealer wasn't about to bust, he can increase his odds at busting and make his agent win; if the dealer still didn't bust, there is yet another opportunity to make the player win by switching the double-down-card. That's a lot of opportunities.
In the video, the double-down-card (2C) was switched for a 10-card (10S), which brought the player's total up to 21. However, the switch-card does not necessarily have to be a 10. If the dealer happens to catch a 17, there are 28 cards in total that can help the player, namely the 7s, 8s, 9s, 10s, Js, Qs, and Ks. In this case any one of those 28 cards will bring the player's total above the dealer's 17. Not to mention that a 6-card will result in a push (a tie), which is also better than a loss.
Such liberal cheating strategies will probably not fly in a regulated casino (mainly because of the grip necessary to facilitate this switch), but anything is possible in a home game or in an after hours club.