Reducing house edge: En Prison rule

One of the basic goals of players in the game of roulette is reducing the advantage the casino has over them, or house edge. There are certain ways that help reduce the roulette house edge. One of the best ways to reduce the house edge is choosing a casino that offers highly advantageous En Prison rule and La Partage rule.

How En Prison rule works

The En Prison rule is offered only by some European casinos offering single-zero roulette wheels - you are not likely to find it anywhere in the United States. It is basically found at both land-based and online casinos offering French roulette tables.

En Prison rule is a rather favorable rule that may help reduce the house edge to 1.35% compared to approximately 2.7% advantage in the European roulette. It only deals with the even money outside bets:

  • Red-Black,
  • Odd-Even,
  • Low (numbers 1 to 18) - High (numbers 19 to 36).

The En Prison rule will only work in case zero is the outcome of the spin while the player has made an even money bet. In such case the player's bet doesn't lose. Instead the player can make two primary choices:

  1. He or she may choose to take back half of the bet and leave the table (thus taking advantage of the La Partage rule).
  2. Otherwise the player postpones the lost bet to the next spin of the wheel, thus sending it to "prison". The bet will be placed in a special section for En Prison bets and the croupier will put a special marker on it. The player may add new bets to the one that is 'imprisoned'.

According to the outcomes of the spin, there are several ways to deal with the player's bet due to the En Prison rule:

  • In case the outcome is zero again, there are two possible tactics the house may apply: either postpone the bet to yet another spin or proclaim the bet has lost.
  • In case the player's bet wins, he or she gets his or her betting money back (but no extra money for the won bet).
  • If the bet loses the house gets the player's money.

As it was mentioned above, you won't regularly find US casinos offering En Prison rule. In case the player's even money bet loses with a zero outcome, the bet is said to be lost.

La Partage rule

The term "La Partage" actually means "sharing" in French. This means that the player shares half his or her even money outside bet with the casino in case the outcome of the spin is zero, which makes it almost similar to the En Prison rule.

What the rule implies is that when the player's even money bet (Red-Black, Even-Odd or Low (1 to 18) or High (19 to 36)) and zero is the actual outcome of the spin, the player loses only half his or her bet to the casino and can keep the other half. Applying the La Partage rule doesn't increase the player's winning odds at roulette, but the influence of zero on the roulette house edge is lower with the rule available.


European roulette
American roulette
No Zero roulette
Roulette Royale