There are a number of other more under-hand ways of gaining an edge over the casino which do not arise often but can shift the edge in your favour considerably.

Tells

In some games of blackjack the dealer deals himself a card face-up and another card underneath, face-down at the start of the game. In games where this is the case it may be possible to get an idea of what card is underneath in certain situations.

When a dealer has an ace as his up-card in most casinos the dealer must look at the card underneath to check if he has a blackjack because if he has a blackjack there is no need to deal anymore cards to the players as his hand can not be beaten. Therefore in this situation when he does not have a blackjack he will leave the card face-down and continue dealing to all the players. He now knows what his two cards are.

Due to this factor some dealers may exhibit an unconscious signal which will indicate to a player how good his cards are. For example if his hand is worth seventeen or more he may raise the corners of his mouth slightly as it is a good hand. If it is lower than seventeen he may not move his mouth at all. With this information you can then choose to "hit" or "stand" accordingly.

To find out if a dealer does give out this information it is worth watching closely (but not too closely) if there is anything he does to indicate how good his cards are. If they do then you can exploit this and keep going back to that particular dealer again and again whenever you visit the casino.

Bent Cards

It is also worth watching the cards closely to see whether any of them have any distinguishing features. When a pack of cards has been used for a long time the occasional card may get bent due to dealer shuffling or perhaps dropping a card on the floor. Obviously if you know what a particular card is you can use this to your advantage if it happens to be the dealers hole card or the card you are about to be dealt.

Another way cards may get bent which can be used to your advantage is as result of the dealer having to check his hole card when his up-card is an ace. When he does this he will usually raise the hole card and the up card slightly off the table and when he has done this several times the ace card can get bent. As the hole card is face-down this card will be bent in one direction and the ace will be bent in the other direction. Therefore the aces can develop a slight bend inwards whereas the hole cards will develop a slight bend outwards. The bend in the card will only be very slight so you have to have keen eyes to spot this, but by gaining the knowledge of which cards are the aces can be advantageous.