# Known Ten gone Wrong Blackjack

#### Dagobert Duck

##### Member
Assume you know the first card dealt to you in Blackjack is an Ace. Your edge will be roughly +51% rule depending
if the first card is a ten its about 13%

but what if i know the dealers upcard before the round is an Ace or a ten? how much -EV is that.
i heard a dealers ace is -35% but dont know about the ten?

Any suggestions on the answer ? book or online sources to find the answer are also very welcome.

thank for the help Dagobert

#### Dagobert Duck

##### Member
johndoe said:
Maybe this is helpful? You can also check the books they refer to.

https://wizardofodds.com/games/blackjack/expected-values/
thanks i already played around with this

https://wizardofodds.com/games/blackjack/appendix/9/euro-6ds17r4/

and sth isnt right with those number i believe. it goes through all possible hand combinations against all
possible dealer up cards but all the probabilties do not add up to 100% but 95.25%.
and just the data only dealers upcard ten. all probabilties should add up to 4/13 =30.77% but they add up to 28.39%

#### DSchles

##### Well-Known Member
Dagobert Duck said:
thanks for the reply Don. However how can the ten for the dealer be more harmful then a ten for the player?
players ten is only 13% or not ?
Why would you think that that wasn't possible? The numbers I gave you are correct.

Don

#### DSchles

##### Well-Known Member
Dagobert Duck said:
thanks i already played around with this

https://wizardofodds.com/games/blackjack/appendix/9/euro-6ds17r4/

and sth isnt right with those number i believe. it goes through all possible hand combinations against all
possible dealer up cards but all the probabilties do not add up to 100% but 95.25%.
and just the data only dealers upcard ten. all probabilties should add up to 4/13 =30.77% but they add up to 28.39%
They add that way because you have to specify whether this is after or before the dealer checks for blackjack; i.e., is it a playable ten or not?

Don

#### Dagobert Duck

##### Member
DSchles said:
The dealer's ace is 34.2%. The dealer's ten is 17.3%.

One source: http://www.bjstrat.net/cgi-bin/cdca.cgi

Don
need to play around with this more but you solved the question just using this site?
DSchles said:
They add that way because you have to specify whether this is after or before the dealer checks for blackjack; i.e., is it a playable ten or not?

Don
ENHC so dealer can still get blackjack , so literally every hand combination even the once where the dealer ends up with blackjack should be included here because the dealer only starts drawing to blackjack after player plays the hand.
at the same time 95.25% of all probabilities included here and dealer bj with permutations is 4.733% which fits a bit to perfect in that gap. Makes me wonder though if those numbers are in fact for enhc as advertised

#### DSchles

##### Well-Known Member
Don't question anything that Mike does. His work is impeccable, and if he writes it, it's correct.

When you write, "but you solved the question just using this site?," I gave you the source of the answer. Another would be Julian Braun's book How to Play Winning Blackjack, which has been out of print for decades.

Don

#### Dagobert Duck

##### Member
DSchles said:
Don't question anything that Mike does. His work is impeccable, and if he writes it, it's correct.

When you write, "but you solved the question just using this site?," I gave you the source of the answer. Another would be Julian Braun's book How to Play Winning Blackjack, which has been out of print for decades.

Don
Come on Don ,
What kind of AP doesn’t ask questions when sth doesn’t look right and just swallows it “because authority XYZ said it so it’s correct “?
Solving puzzles is the whole point of this game.
And having the best answer makes you stay ahead.
i know Mike for a while now.
lots of respect for the guy. he is very good, but it wouldn’t be the first time I first sth incorrect on his site.
and as I mentioned above the explanation that those 4.7% is for the dealers Bj scenarios does Not make sense because it’s ENHC.
So potential any dealer blackjack happens after all players decisions so you can’t beforehand exclude those scenarios if all you you have is a dealers up card

#### Dagobert Duck

##### Member
thanks for the link and the book recommendation.

as I said i have not fully understood the whole functionality of that site u sent.
could not get the single up card thing to work but was also tired.
I will get it though thanks a lot for your help