Picture the worst moment a no hole card table can produce. You split a pair, one of the new hands doubles, the dealer finally draws a second card, and it completes a blackjack. Everything you put on the table is now in limbo. How much of it you lose is not decided by the cards and not decided by your play. It is decided by a settlement rule that is rarely printed: the abbreviations OBO, OBBO and BB+1, and the full European rule they soften.
In a game where the dealer takes a hole card and peeks at it, this moment cannot happen. The peek rule exists precisely to resolve the worst case while every player has only a single unit at stake: the dealer checks for blackjack before anyone acts, and if it is there, the hand is over before any doubling or splitting money exists. The no hole card family of rules, which our piece on European blackjack and the no hole card rule introduces, moves that discovery to the end of the round. What that piece covers in one sentence, that some tables soften the blow by taking only the original bet, is worth a whole article, because the versions of that softening have names, prices and one worked example.
All costs below are Wizard of Odds' figures for the effect on the player's expected return, each compared with an otherwise identical game where the dealer peeks.
Four settlements, one table
A no hole card game needs some rule for what a late dealer blackjack takes. Here are four, with what each one costs.
| Settlement | What the player loses to a dealer blackjack | Cost vs a peek game |
|---|---|---|
| Full European no hole card | All bets made, including doubles and splits; a player blackjack pushes | 0.11 percent |
| OBBO, original bets and busted only | The original bet on each hand, plus any busted bets | 0.03 percent |
| BB+1, busted bets plus one | All busted bets, plus one unit | 0.01 percent |
| OBO, original bets only | The original wager, nothing else | Nothing relative to the peek game |
The full rule is the expensive one, and Wizard of Odds splits its 0.11 percent into 0.08 from doubling and 0.03 from splitting: the tax falls exactly on the money you add after seeing your cards. OBBO costs 0.03 percent, and Wizard of Odds says the rule is, as far as its author knows, confined to some parts of Australia and Malaysia, and notes that some sources use the name OBBO for BB+1. BB+1 costs 0.01 percent, and Wizard of Odds calls it an Australian rule.
OBO is the interesting row, because it has no price to quote. Under OBO the player loses only the original wager to a dealer blackjack, and that is exactly what the player loses in a game where the dealer peeks. The extra doubling and splitting money comes back, so the outcomes match the peek game's outcomes, and the rule costs nothing relative to it.
One hand, three settlements
Wizard of Odds makes the differences concrete with a worked example, worth reproducing exactly. A player splits 8s and ends up with three hands: a 20, a doubled 19, and a busted hand. The dealer then turns up a blackjack. Count the damage under each rule.
Under BB+1 the loss is 2 units: the busted hand, plus one unit taken from the 3 units still standing on the table. Under OBBO it is 3 units: the busted hand, plus one original bet for each of the two unbusted hands. Under the full European rule every unit wagered is lost, and the arithmetic is plain: three original units plus one for the double makes 4 units. Same cards, same decisions, and the settlement rule is the entire difference between losing half of what you put out and losing all of it.
21 TrainerFree on iPhone and Android. Nine casino presets and full rule customization, with instant feedback and an explanation on every hand.
Get the app
The partial peek rules, and a ten fold gap
Two hybrid rules sit between the peek game and the no hole card game, and their costs are strikingly uneven. If the dealer does not peek with an ace up but does with a ten up, the cost is 0.01 percent. If the dealer does not peek with a ten up but does with an ace up, it is 0.10 percent, ten times as much. In each case a blackjack that is not checked for takes all bets, including doubles and splits.
Why the gap runs that way is worth handling carefully. A dealer blackjack is equally frequent with a ten up and with an ace up: 4/13 x 1/13 in either order, about 2.37 percent of hands from a fresh shoe. So the difference between 0.01 and 0.10 cannot come from how often the disaster happens and must come from how much extra money basic strategy has on the table when it does. That is consistent with the chart rather than proof of the figures: in the four to eight deck chart where the dealer stands on soft 17, hard 11 doubles against a ten but only hits against an ace, and our piece on doubling hard 11 shows how central that hand is. The sizes of the two costs themselves are Wizard of Odds' result.
One more asymmetry between the two upcards is ritual rather than arithmetic: with an ace up the table usually gets a formal warning in the shape of the insurance offer, the side bet our piece on why basic strategy never takes insurance dismantles. With a ten up there is no offer at all, just the settlement rule waiting in silence.
How the strategy responds
Under the full European rule the chart itself changes, because the tax on after-the-fact money changes the math of putting that money out. The adjustments our no hole card piece lists all follow one principle: against a dealer ten or ace, commit no chips that a late blackjack can sweep. Hit hard 11 against a 10 instead of doubling, even though doubling is the peek game's play. Do not split 8s against a 10 or an ace, since the case for always splitting 8s assumes the dealer cannot confiscate the second hand. Doubles against a ten or ace disappear generally. Everything against 2 through 9 is untouched, because those upcards cannot hold a blackjack.
Under OBO nothing changes from the peek game, for the reason the table gives: the outcomes are the same, so the optimal plays are the same. The softer settlements sit in between, and the honest summary is that none of them moves the needle much. Even the full rule's 0.11 percent is a modest line on the ledger compared with the payout and deck count items our rule stacking guide prices, and it is far from the roughly 1.4 percentage points a 6:5 blackjack payout costs.
The question worth asking
Here is the practical problem with all of this: the settlement rule is rarely printed. The felt carries the payout line and the soft 17 rule, the placard usually carries doubling restrictions and surrender, and neither usually says what happens to your doubled bet when the dealer's second card completes a natural. Our piece on how rules travel and our rule card glossary cover what is written down; the settlement rule belongs to the category that has to be asked about, before the first hand rather than after the hand that makes the answer expensive.
One boundary note for practice: 21 Trainer deals with a hole card in every preset and does not model any of these settlements, so the no hole card adjustments are learned from the changed plays themselves rather than played out in the app. Learning to notice what a rule card says, and what it leaves out, is the general skill the trainer's rule settings are for.
Frequently asked questions
What does OBBO mean in blackjack?
Original bets and busted only. When the dealer turns up a blackjack in a no hole card game played with OBBO, the player loses the original bet on each hand plus any busted bets, and the doubled part of any hand that did not bust is returned. Wizard of Odds prices the rule at 0.03 percent against the player compared with a peek game, says that as far as its author knows it is confined to some parts of Australia and Malaysia, and notes that some sources use the same name for BB+1.
What does BB+1 mean in blackjack?
Busted bets plus one. Under BB+1 a dealer blackjack costs the player all busted bets plus one additional unit, and the remaining bets are returned. Wizard of Odds prices it at 0.01 percent against the player compared with a peek game and calls it an Australian rule. It is the cheapest of the three no hole card settlements priced there.
What is the difference between OBO and the full no hole card rule?
OBO, original bets only, takes just the original wager when the dealer has blackjack, so doubles and splits give back their extra money. That is exactly what a player loses in a game where the dealer peeks, so OBO costs nothing relative to the peek game. The full European no hole card rule instead takes every bet on the table, doubles and splits included, except that a player blackjack pushes, and costs 0.11 percent.
What happens if you double and the dealer has blackjack in a no hole card game?
It depends on the settlement rule. Under the full European rule the doubled bet is lost too, both units. Under OBO only the original wager is lost and the doubling money comes back. OBBO loses the original bet plus any busted bets, and BB+1 loses all busted bets plus one unit. This is why the strategy chart itself changes under the full rule but not under OBO.
What is a partial peek rule in blackjack?
A table where the dealer peeks with one dangerous upcard but not the other. If the dealer does not peek with an ace up but does with a ten up, Wizard of Odds puts the cost at 0.01 percent; if the dealer does not peek with a ten up but does with an ace up, it is 0.10 percent. In each case a blackjack that is not checked for takes all bets, including doubles and splits.