The partage rule
When the zero comes up, a bet on red, black, odd, even, low or high loses only half. It is the most generous rule in the whole of roulette, and it cuts the casino's edge in two.
What the rule says
The zero comes up. Every inside bet is lost, as usual. But on the even-money bets — the six boxes that pay 1 to 1 — the dealer takes only half the chips and gives the other half back. A 10-chip bet on red becomes 5 chips returned and 5 chips lost.
That is all of it. The rule applies to the even-money bets and to nothing else: a straight up, a split, a dozen or a column loses in full on the zero.
| Bet | Without partage | With partage |
|---|---|---|
| Red, black | −10 | −5 |
| Odd, even | −10 | −5 |
| Low, high | −10 | −5 |
| Dozen, column | −10 | −10 |
| Straight up, split, corner… | −10 | −10 |
Why the edge falls to 1.35 %
Take one chip on red, and walk through the 37 pockets one at a time.
- 18 red numbers: you win a chip.
- 18 black numbers: you lose a chip.
- the zero: you lose half a chip.
Over 37 spins the account reads +18 − 18 − 0.5 = half a chip lost for 37 staked, or −1.35 %. Without the rule the zero cost a whole chip and the sum came to −1/37, the usual 2.70 %.
Put another way: the even-money bets become the best wager on the table, twice as good as everything else. It is the only time the equality between bets is broken, and it is broken in the player's favour.
En prison, the other version
Some tables apply en prison instead of partage. On the zero the bet is neither lost nor returned: it is imprisoned, marked with a chip, and played again on the next spin. If it wins, the player takes the stake back — with nothing on top. If it loses, it is swept away.
The outcome is nearly the same, and slightly worse for the player: an imprisoned bet has only 18 chances in 37 of coming back, which works out at an edge of 1.39 % against 1.35 % for partage. The difference is a second zero landing while the bet sits in prison, which usually loses it for good.
Worth remembering: partage and prison look alike, partage is marginally better, and neither applies anywhere but the even-money bets. A table that offers neither keeps its 2.70 % on everything.
Where you find it
The rule comes from French roulette and still turns up on its tables, particularly in France, in Monaco and in several European casinos. It is often reserved for tables with a high minimum: it is what the house offers in return when the stakes go up. American double-zero wheels almost never apply it.
At this table
Partage is applied, always. When the zero comes up, half of every even-money bet goes back into the balance, and the announcement says so: "The zero shares: half the stake comes back." The half is rounded up, since a chip cannot be cut in two.
Back to the roulette — the returned half shows as soon as the zero lands.