D’Alembert system

This is a progression system that helps win back losses in small steps instead of all at once like the Martingale. It was engineered for use on the even chance bets on a roulette table but can be used on any even chance bet.

This system works on the theory that over time there will be an equal number of wins for both the player and the banker. If a player starts a session by placing one unit ($1, $5 or any other value) on the player to win, after a losing hand he will increase the subsequent bet by one unit and after a winning bet will decrease the next bet by one unit. So if he were betting on the player and the results were - loss, loss, loss, win, loss, win, win, loss, win, win, win - then the bets placed would be as follows (the numbers in brackets show the level of your bankroll after the spin):

1 (-1), 2 (-3), 3 (-6), 4 (-2), 3 (-5), 4 (-1), 3 (+2), 2 (+0), 3 (+3), 2 (+5), 1 (+6)

This sequence would close with a win of £6. As soon as the number of wins is equal to the number of losses plus one, then the sequence ends with a win. Also notice that after the 7th, 9th and 10th spins the player was showing a profit, because the bets placed on winning spins are one unit greater than the previous losing spin. Having the possibility of a positive bankroll before the sequence is complete allows the player to cut the session short after a small win rather than risking the chance of the session ending badly.

Although this system lessens the chances of losing your bankroll the possibility of this happening is still there. A long sequence of consecutive losses or a period of time where the banker wins more often than the player will soon put the system in a position where it becomes almost impossible to recover. As always the house edge works on every spin, and so increasing your bets will eventually increase your losses.