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The Contra d'Alembert Roulette System

Contra d'Alembert Roulette System Strategy

Also known as the Reverse d'Alembert system, this variation of the popular d'Alembert system uses a positive progression betting pattern with 'even chance' bets. It requires the bet to be raised on a win and lowered on a loss. Like its predecessor, this system offers the benefit of a slow bet progression which is easy on the bankroll.

How to Use the Contra d'Alembert

The process follows the original closely. It has you begin each session with 1 unit and start over when you profit. The key difference being that you must add a unit on a win and subtract a unit on a loss. To use this during gameplay, follow these steps:

  • Bet 1 unit on an 'even-chance' bet of your choice.
  • If you win, add 1 unit to your total bet going into the next spin.
  • If you lose, take away 1 unit from your total bet.
  • Repeat this process until you reach your personal profit goal, personal loss limit or personal time limit.
  • Once you profit, start over with 1 unit.

Which Bets are Best for This System?

Even-chance bets have a nearly 50-50 chance of winning or losing each spin making them ideal for this particular roulette strategy. These include black/red, low 18/high 18 and even/odd. While they have the highest odds of winning, even-chance bets also have the lowest payout: 1/1.

Sit Tableside and Watch This System in Action

Let's have a look at how this system plays out in a real-world scenario. You've just learned the basics and are eager to try them out your favorite casino, so you begin a roulette session with 1 unit of C$5. Your personal profit goal is 1x the total bet, and your personal loss limit is $250. With this in mind, you place a chip on red.

  • The roulette wheel whirls around, and the ball plinks a few moments until it finally lands into the 15 black pocket. This loss sets you back C$5. Since this is the beginning of a session and taking away a unit would leave you with no bet, you place a chip on red again.
  • The wheel spins again and the ball lands in the 6 black pocket resulting in a loss of another C$5. So, you again place a chip on red for a total bet of C$5 going into the next spin. So far, your net loss is -C$10.
  • Fortunately, the ball chooses 21 red for a payout of C$5 putting your net loss at C$5. You add 1 unit for a total bet of C$5.
  • Luck strikes again when the ball lands on 16 red. The C$5 payout brings you to a C$5 net profit. You've reached your profit goal, so you end the session here.
"Seasoned gamblers that prefer this method recommend selecting an initial bet of less than 5% of your personal loss limit."

If you're familiar with the d'Alembert system, this reverse sequence should feel familiar. 2 initial losses followed by 2 wins results in a profit of 1x the starting bet. Let's have a look at how this plays out during a longer session.

Total Bet
Win/lose
# of units
Net Profit
C$5
Lose
+1
-C$5
C$10
Lose
+1
-C$15
C$15
Lose
+1
-C$30
C$20
Lose
+1
-C$50
C$25
Win
-1
-C$25
C$20
Win
-1
-C$5
C$15
Win
start over
C$10
C$5

This 7 round session results in a profit of 2x the starting bet. After an initial losing streak of 4 spins, it takes 3 rounds to recover.

This System's Logic

The main goal of this system is to slow the bet progression even more than the original while keeping the advantages of simple rules and even-chance odds. When compared side by side, the difference in expense is clear. Have a look at these 7 spin sessions that start with 4 losses followed by 3 wins.

D'Alembert Negative Progression
Total Bet
Win/lose
# of units
Net Profit
C$5
Lose
+1
-C$5
C$10
Lose
+1
-C$15
C$15
Lose
+1
-C$30
C$20
Lose
+1
-C$50
C$25
Win
-1
-C$25
C$20
Win
-1
-C$5
C$15
Win
start over
C$10
C$5
D'Alembert Positive Progression
Total Bet
Win/lose
# of units
Net Profit
C$5
Lose
-1
-C$5
C$10
Lose
-1
-C$15
C$15
Lose
-1
-C$30
C$20
Lose
-1
-C$50
C$25
Win
+1
-C$25
C$20
Win
+1
-C$5
C$15
Win
start over
C$10
C$5

The original requires adding to the bet on a loss driving the expense up. You can see the d'Alembert system is down almost double from the Contra d'Alembert system by the end of the fourth spin. Both eventually recover ending with a profit of 2x the starting bet.

Let's compare the two during a 7 round session with an initial winning streak of 3 followed by a losing streak.

The d'Alembert System requires players to add a unit after each loss, but take one away after a win making it difficult to take advantage of a series of initial wins. Ultimately, the net profit amounts to only 1x the total bet.

Round
Bet
Win/Lose
Net Profit
1
C$5
Win
C$5
2
C$5
Win
C$10
3
C$5
Win
C$15
4
C$5
Lose
C$10
5
C$10
Lose
C$0
6
C$15
Lose
-C$15
7
C$20
Win
C$5

The Contra d'Alembert System actually fares much worse under identical circumstances. Ultimately, the net loss is 2x the initial starting bet.

Round
Bet
Win/Lose
Net Profit
1
C$5
Win
C$5
2
C$10
Win
C$15
3
C$15
Win
C$30
4
C$20
Lose
C$10
5
C$15
Lose
-C$5
6
C$10
Lose
-C$15
7
C$5
Win
-C$10

Either system works best short term. If your session happens to start with a winning streak, keep in mind that the Contra d'Alembert doesn't handle a losing streak well. This is mainly due to d'Alembert's assumption that there is a greater chance that a win will follow shortly after a loss more often than not. The French mathematician wasn't entirely wrong. In theory, during an extended session of thousands of spins, even-chance bets should win about once every two spins.

However, d'Alembert didn't account for the variance of longer winning and losing streaks that commonly occurs in games of chance. Nor did he account for the house edge that slightly reduces the odds at the roulette table.

That is why we recommend ending your session on the first loss and starting over with 1 unit despite your personal profit goal when your session begins with a winning streak. If the session above had stopped after spin 4, it would have ended on a 2x/bet profit.

Advantages & Disadvantages to Consider

By reducing the bet after a loss, the Contra d'Alembert system is able to suit the most conservative budget. This variation also inherits most of the strengths of the original including high, even-chance odds and flexibility in choice of casino due to slow bet progression.

The trade-off is that even-chance bets pay 1/1 on a win which is the lowest out of all the bet options. Also, the original recovers better after an initial winning streak followed by a losing streak.

Does the Contra d'Alembert Work?

Well, the answer to that question may not be as simple as you might think. With the right sequence of wins and losses, you can certainly turn a profit. However, the positive progression struggles at times with generating enough profit to overcome losses. The trick is knowing the strengths and weaknesses of the system, so that you can use it effectively tableside.

You have already seen how it struggles to recover from a session that begins with a winning streak, and how it fares pretty much the same as the original when the session starts out with a losing streak. Have a look at how it does with a more irregular win/loss variance.

Total Bet
Win/ Lose
# of Units
Win/ Lose
Total Net Profit
C$5
Lose
-1
-C$5
-C$5
C$5
Win
+1
C$0
C$0
C$10
Win
start over
C$10
C$10
C$5
Lose
-1
-C$5
C$5
C$5
Win
+1
C$0
C$10
C$10
Lose
-1
-C$10
C$0
C$5
Win
+1
-C$5
C$5
C$10
Lose
-1
-C$15
-C$10
C$5
Win
+1
-C$10
-C$5

Notice how, after 2 consecutive wins in a row, the system struggles to get a foothold in the profit margins. Even though there are 5 wins out of 9, there is still a net loss of 1x the initial bet.

Obviously, if the session had ended after the third round, it would have resulted with a net profit of 2x the initial bet. That is why it is essential to end your session after gaining a profit.

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Always Gamble Responsibly

  • The Contra d'Alembert may use a slow bet progression, however, this does not ensure that you will not overspend.
  • Set a personal loss limit, time limit and profit goal before beginning each session.
  • Remember, pocket the profit from each session and begin again with 1 unit rather than risk losing what you've won to chase after a winning streak that might not occur.
  • As with any roulette system, the Contra d'Alembert does not guarantee to play out the way you expect. Roulette is a game of chance. Anything can happen!

Is This the Method for You?

The extremely slow bet progression makes this ideal for players on a budget. When used correctly, expect it to produce low-end profits in the short term. Obviously, the positive bet progression will help build profit potential during winning streaks, however, it takes good instincts and sense to turn that to your advantage. If you like low-pressure systems that don't break your bankroll, then this could make a very good fit.