What is the D'Alembert system in roulette? The D'Alembert roulette system tells you how much to stake when betting odd/even, red/black or high/low at the roulette wheel. Increase your bet amount by 1 unit after a win, and decrease it by 1 unit after a loss. The aim is to generate a modest overall profit.

That's because roulette is a pure game of chance and the odds always favor the house (i.e., the casino), no matter which bet or combinations of bets you make, and regardless of what numbers have come up in the recent past. You will never, in the long run, overcome the house edge.