Roulette gamers in the know are aware that the best type of no deposit casino bonus they can get playing roulette is to play European roulette. Choosing to play on a European online casino roulette wheel, which features just one zero pocket (as opposed to the American roulette wheel that features a second, double-zero pocket) lowers the house edge.
Most casinos have all but eliminated the European roulette wheel. However, you can still find European roulette, including the en prison rule, at select casinos.
Advantage of En Prison
The en prison rule is incorporated into certain variations of European roulette. The En Prison rule lowers the house edge on even money bets. Therefore, if you’re playing a European wheel that features en prison, you’ll want to focus on the even money bets to be able to look forward to getting about half your money back in the long run in cases where the ball lands on the zero.
If you activate this rule, half of specific bets will be returned. That means that you lose only half as much as on any other loss. Basically, it protects the player from a total loss at the cost of half their bet.
For example, if you have a $20 bet riding on black and the ball lands on zero, you don’t win or lose but you will be “locked up” for one more spin. On the next spin, if the ball lands on red, you lose. If the ball lands on black, the house will return your original bet of $10 but you won’t win anything. If the ball again lands on zero, your bet stays imprisoned for another round.
There’s an alternate version of the en prison rule that gives players the chance to rescue an even higher percentage of their money. Instead of the casino simply returning half of the player’s money, the money becomes “imprisoned.” The money is held over for the next bet.
If the player wins on a second spin, the bet is “rescued”. No winnings are paid out but no additional deposit is necessary either. If a bet is unsuccessful, the player loses the bet for good.
In some casinos,if the ball lands on a zero for a second time, it gets a bit confusing. Some casinos ignore that result and simply leave the bet imprisoned. It’s final call – lost or rescued – is based on the next result that isn’t a zero. In other casinos, such a toss will be regarded as a loss just like any other.
There are also casinos that treat it as a double or triple imprisonment. If you’re playing at one of those casinos, you can still try to rescue your bet on a second consecutive zero, which is more difficult. First, you must win one spin which will get your bet out of “double imprisonment.” Now you’re back to the standard en prison position and you can attempt to rescue your money.
If you experience any loss during this process, you lose the money altogether. You can also check if your casino offers triple imprisonment or more when consecutive zeroes are hit. It means taking a big chance, since hitting that many zeroes in a row is pretty rare, but you never know.
In some casinos, you aren’t given an option as to how you want to treat your en prison bet. Either the casino will use the en prison rule and give you half your money back, or you’ll have to wait out the imprisonment.
If your casino does give you a choice, you should take your money back. An additional zero will hurt you (you could lose your bet or find yourself in double imprisonment) so it's worth the 50/50 chance of saving your bet which will allow you to recoup half the money.
There’s one additional issue to take into consideration -- a French rule in which zeroes have no impact on the results. If that rule is being used, you can safely opt for either rule since, in the long run, you’ll get the same results either way.
In short, the en prison rule, which is only available for European roulette games, is worth the effort. The en prison rule lowers the house edge to 1.35 percent, which is better than playing non-en prison rule games. Don’t forget that the rule applies only to even-money bets.