The D’Alembert System is a negative progression betting system that is used in Blackjack. A betting system is a mechanized form of betting whose purpose is to consistently result in winnings. There are various kinds of betting systems available in casinos. Flat betting systems are when the player bets the same amount no matter what. A positive progression system is when the player increases his wagers by one unit whenever he wins. A negative progression system is when the player increases his wagers by one unit whenever he loses. Betting systems require the player to change the size of his bet based on some condition in casino gambling. All are based on the past bets and the result of the play.

The D’Alembert system is rather simple and easy to use. The player raises his wager by one unit when he loses and lowers it by one unit when he wins. For example, if the player bets one unit and loses, his next bet would be for two units. If he wins, he lowers his bet to one unit.  If he loses, he raises his bet to three units. He continues to play in this manner, raising his bets when he loses and lowering them when he wins. The D’Alembert system is often described as a twisted negative progression system because it can continue for the length of the playing session. It is possible for the player to hit the table betting limits if he experiences a prolonged losing streak. Like any betting system, this one is not recommended for serious play. Various online casinos are also there for betting in blackjack.