En Prison: the stake that waits for the next spin
En Prison is the older of the two French zero rules and the one you are less likely to meet online. Instead of returning half of an even-money stake on a zero, the table locks the whole stake in place for one more spin. Win that spin and the stake comes back; lose it and the stake is gone. The effect on the house edge is almost identical to La Partage, but the mechanics are different enough to be worth understanding before you sit at a table that uses it.
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The rule, step by step
- You have £10 on red. The ball lands on zero.
- Your £10 is not removed. It is marked as imprisoned and stays on red.
- The next spin is played. You cannot change or withdraw the imprisoned bet.
- If red wins, your £10 is returned to you. No winnings, just the stake.
- If black wins, the £10 is lost.
- If zero comes up again, the table's own rule applies. Common versions: the stake is lost; the stake stays imprisoned for another spin; or, rarely, half is returned.
What it costs
On the zero spin itself you lose nothing yet. On the follow-up spin you have an 18 in 37 chance of getting the full stake back and a 19 in 37 chance of losing it (treating a second zero as a loss, which is the most common rule). The expected value of the imprisoned stake is 18/37 of its face value, which means the zero costs you 19/37 of the stake rather than all of it. Averaged over all spins that works out to an edge of about 1.39%, so close to La Partage's 1.35% that the two are usually quoted together.
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Compared with La Partage
| La Partage | En Prison | |
|---|---|---|
| On zero | Half the stake returned now | Whole stake held for next spin |
| Settles | Immediately | After one more spin |
| Edge on even-money | 1.35% | About 1.35–1.39% |
| Online availability | Common on RNG French tables | Rare |
| Second zero | Not an issue | Depends on table rules |
For the player the practical difference is variance. La Partage gives you a certain £5 back; En Prison gives you a 48.65% chance of £10 and otherwise nothing. Same average, bumpier ride.
Why it is rare online
RNG tables are built around one spin, one settlement. A bet that carries over complicates the interface and the maths, so most providers chose La Partage for their French tables. Live tables occasionally offer En Prison, usually in studios aiming at a traditional European feel, and the dealer physically marks the imprisoned chips.
If you find one
Read the second-zero rule before betting. Keep the stake at a level where having it locked for a spin does not bother you. And remember that only even-money bets go to prison; everything else on the layout loses on zero in the usual way.
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Quick answers
Is En Prison better than La Partage?
They cost almost exactly the same, 1.35% on even-money bets. La Partage settles at once; En Prison needs another spin. Online, La Partage is far more common because RNG games prefer bets that settle each round.
What if zero comes up twice with En Prison?
Rules vary. Some tables lose the imprisoned stake, some keep it imprisoned, a few apply a "double prison". The help screen should say. If it does not, assume the stake is lost on a second zero.