The D’Alembert system, also called montant et demontant (from French, which means up and down), is often called the pyramid system. It is based on a mathematical balance theory designed by the French mathematician of the same name. Like Martingale, this system is mainly applied to outside bets and even money, and is liked by players who want to keep bets and losses to a minimum. The progress bet is very simple: After each loss, you add one unit to the next bet, and after each win, one unit is deducted from the next bet. Starting with the initial bet, say, 1 unit, the loss will increase the next bet to 2 units. If this is followed by a win, the next bet is 1 unit.
This betting system depends on the gambler’s mistake – that players are more likely to lose after winning, and more likely to win after losing.
How it works
The basic system is to add 1 unit to defeat, and subtract 1 unit to win, with a minimum bet of 1 unit. Example bets with D’Alembert:
While D’Alembert works well for short periods of time, this is basically flawed for any casino with a profit, because the size of the bet depends on the total number of wins and losses. Assuming a 1% profit, you have to bet at a 49.5% chance to win to get 2x profit per bet. This means that statistically, you will lose 1% more bets than you won, causing your bets to slowly and steadily increase until they become greater than your balance, even though there may be profits above all.
Although all betting systems are basically the fault of gamblers, d’Alembert is the most obvious flaw for long-term use.
Deviations from d’Alembert’s strategy include “stretching” your victory or defeat. This means that you must press more than one win or lose in a row to reduce or increase your bet. Below is an example of a bet from above, while stretching a loss to 2 (only increases in 2 consecutive losses)
D’Alembert can be reversed as a positive development system, which means you increase your bet size when you win and reduce your bet size when you lose.