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Definition

En Prison

Also known as In Prison, Imprisoned Bet

By Reviewed Editorial policy

In short

En Prison holds your even-money bet for one more spin when zero lands, rather than losing it. Win the next spin and the stake is returned; it halves the house edge on those bets to 1.35%.

En Prison, “in prison”, applies to even-money roulette bets when zero lands. Instead of losing, the bet is locked for one more spin.

How it resolves

The dealer marks your bet with a marker. On the next spin:

  • Your bet wins → the stake is returned. You do not win anything, but you do not lose
  • Your bet loses → the stake is lost
  • Zero again → rules vary. Most tables lose the bet; some imprison it a second time

The effect

Halving the loss from a zero halves the house edge on even-money bets:

  • Standard European: 2.70%
  • With En Prison: 1.35%

Identical to La Partage. The two rules reach the same expected value by different mechanisms.

Which is better

Mathematically, neither, the expectation is the same.

Practically they differ in feel. La Partage gives you half your money back immediately and ends the matter. En Prison keeps the full stake alive, so there is a real chance of getting all of it back, balanced against the chance of losing all of it.

For a bettor who wants to leave, La Partage is more convenient. For one who is staying anyway, En Prison is identical in value and slightly more interesting.

Scope and availability

As with La Partage, the rule applies only to even-money bets. Red/black, odd/even, high/low. Dozens, columns and inside bets carry the full house edge.

En Prison is found on French roulette tables and at some European casinos. It is less common online than La Partage, partly because the imprisoned-bet mechanic is more awkward to represent in software.

Where either rule is available, the even-money bets on that table are the best value in roulette by a considerable margin.

Common questions

How does the En Prison rule work?

Your even-money bet is held for one more spin when zero lands rather than being lost. Win the next spin and the stake is returned, though you win nothing. It halves the house edge on those bets to 1.35%.

Is En Prison better than La Partage?

Mathematically they are identical. La Partage settles immediately and returns half, while En Prison keeps the full stake alive with a real chance of getting all of it back or losing all of it.

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