Math behind EU and US bj

Hello, from a mathematical point of view what does it change, if something changes, between EU and US bj when the dealer has the ace? So if we have a pair of 8s or aces, according to the basic strategy we should always split them, but how does our odds change if we know before whether the dealer has a bj or not? I refer to a situation where the number of decks is the same, and the dealer stands on all 17s with no surrender option. Thanks

Quote: Magicall

Hello, from a mathematical point of view what does it change, if something changes, between EU and US bj when the dealer has the ace? So if we have a pair of 8s or aces, according to the basic strategy we should always split them, but how does our odds change if we know before whether the dealer has a bj or not? I refer to a situation where the number of decks is the same, and the dealer stands on all 17s with no surrender option. Thanks
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The notable difference with EU No Hole Card rules is that the dealer does not and cannot peek when he has a ten. Thus he can end up with a Blackjack and beat you, so correct strategy if dealer has a ten and player has eleven is to Hit. In US rules, you would double 11 vs ten.
Also with no peek rules you don't split aces against an ace, again because the dealer can end up with Blackjack and so he has a bigger chance of beating split aces..

Quote: OnceDear

Quote: Magicall

Hello, from a mathematical point of view what does it change, if something changes, between EU and US bj when the dealer has the ace? So if we have a pair of 8s or aces, according to the basic strategy we should always split them, but how does our odds change if we know before whether the dealer has a bj or not? I refer to a situation where the number of decks is the same, and the dealer stands on all 17s with no surrender option. Thanks
link to original post

The notable difference with EU No Hole Card rules is that the dealer does not and cannot peek when he has a ten. Thus he can end up with a Blackjack and beat you, so correct strategy if dealer has a ten and player has eleven is to Hit. In US rules, you would double 11 vs ten.
Also with no peek rules you don't split aces against an ace, again because the dealer can end up with Blackjack and so he has a bigger chance of beating split aces..
link to original post

Ok thanks, but for example in the evolution gaming US online blackjack the dealer does not peek when he has a ten but only if he has the ace, so in that case the correct move is also to hit right?

Quote: Magicall

Hello, from a mathematical point of view what does it change, if something changes, between EU and US bj when the dealer has the ace?
link to original post

Welcome to the forum.

The first part to look at is "Which rules are different?"

I can think of at least 8 different common sets of US blackjack rules; I expect there is some variation under the common EU rules as well.

So, for each game, what are the rules?

Naturals: 3:2, 6:5, 1:1? Player always wins?
H17, S17?
Hole card, no hole card?
Peek 10/A, Peek 10, Peek A, No Peek? (Peek here can mean either a lift or a device)
Double any, Double any (except natural), Double any (except soft), Double 9/10/11 only, Double 10/11 only, Double 11 only?
Double after split allowed?
Resplit aces allowed? Hit split aces allowed?
Dealer natural handling (for no hole card/no peek): Lose all, lose original only, lose original & busted only?

There may be a few I forgot.

Natural pays 3:2 for both.
Stand on every 17s for both.
Hole card for US no hole card for EU.
Peek only with Ace for US. No hole card for Eu.
Double any for both.
Double after Split not allowed..
Resplit aces not allowed for both, it's not allowed a split after split for both as well. Hit after splitting aces I think it's not allowed in any blackjack.
Dealer natural handling for no hole card/no peek: lose all.

Quote: Magicall

Quote: OnceDear

Quote: Magicall

Hello, from a mathematical point of view what does it change, if something changes, between EU and US bj when the dealer has the ace? So if we have a pair of 8s or aces, according to the basic strategy we should always split them, but how does our odds change if we know before whether the dealer has a bj or not? I refer to a situation where the number of decks is the same, and the dealer stands on all 17s with no surrender option. Thanks
link to original post

The notable difference with EU No Hole Card rules is that the dealer does not and cannot peek when he has a ten. Thus he can end up with a Blackjack and beat you, so correct strategy if dealer has a ten and player has eleven is to Hit. In US rules, you would double 11 vs ten.
Also with no peek rules you don't split aces against an ace, again because the dealer can end up with Blackjack and so he has a bigger chance of beating split aces..
link to original post

Ok thanks, but for example in the evolution gaming US online blackjack the dealer does not peek when he has a ten but only if he has the ace, so in that case the correct move is also to hit right?link to original post

If he has a ten, does not peek, then hit when you have 11. If he has an ace, peeks and does not have Blackjack, then I believe it's a very close call. I read various strategy engines that say hit 11 vs ace.. With No hole card game, definitely hit 11 vs ten or ace.