How best to defend against a lone call

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raydog
Posts: 238
Joined: Thu Sep 16, 2021 6:56 pm

How best to defend against a lone call

Unread post by raydog » Thu Jun 02, 2022 1:53 pm

I'm seeking the advice of the experts here, as I try to refine my euchre program.

Imagine S4 (dealer) is dealt A-10S + QH + J-9C, with JS turned.
[as an aside, do you prefer me listing the cards this way, or using the graphics?]

S4 calls alone in S. Should they discard the 9C or the QH? This is something I can't simulate, because the results are dependent on how I program S1 and S3 to play; so I introduce my own bias. I imagine this is situation dependent - playing against randos or know expert players - but I'd like to hear the verdict in either case.
_______________________

2nd scenario. Dealer has the same hand, and S1 is dealt Q-9S + KH + Q-JD. Should S1 lead the KH or the QD?

And a corollary question: if I lead the QD and dealer wins with the AD, should I later discard the JD or the KH [this will likely be a decision to make on the 4th trick]? Would the answer change if I originally held the J-10, led the JD, and dealer won with the KD?



irishwolf
Posts: 1273
Joined: Tue Apr 24, 2018 9:33 pm

Unread post by irishwolf » Fri Jun 03, 2022 12:15 am

RAY,

Some slightly questions about the Dealer discard, but not in my book. My answers are in Blue.

Here is what and why I would do:

1. DEALER DISCARD: I like discarding the 9C. Four other cards win this one vs only AH/KH wins the QH. Loner rate will not be nearly as good discarding the QH, IMO. Just a statistical issue, don't get crazy! Imagine S4 (dealer) is dealt A-10S + QH + J-9C, with JS turned.

Graphics is only fluff for me. [as an aside, do you prefer me listing the cards this way, or using the graphics?]

2. S1 DEFENDS THE LONER ABOVE: This is actually an easy question. You have two off suits. S1 is dealt Q-9S + KH + Q-JD. Should S1 lead the KH or the QD? CONSIDER FIRST OF ALL (MY DATA) THAT DEALER WILL MORE OFTEN HAVE A DOUBLETON TRAILER. You have one doubleton and two weak Stoppers.
No question you MUST lead the KH. And the KH is useless if the Dealer has the AH +XH.
Sometimes he just might have a singleton trailer. You eliminate the Hearts and won't squeeze yourself. It is always the job of S1 to communicate what he is NOT saving but you have no Club to do this. S3 will know on trick 4 that you have a doubleton Diamond. Just pray!

So what is the downside of leading the KH? Not many!
If S3 has two aces, your 4th trick Diamond tells him you have another Diamond and that is after the Dealer who must play first. And S3 can now save Clubs doubleton or singleton. And this is the reason that 9C is a bad KEEPER.
The only issue is if Dealer has KD singleton and S3 had AD/AC. You can never cover it all!

3. Exactly the issue is that you SQUEEZE YOURSELF LEADING DIAMONDS. If you read what I said in 2. above you have your answer - save the Diamond. But Never ever do that! And a corollary question: if I lead the QD and dealer wins with the AD, should I later discard the JD or the KH [this will likely be a decision to make on the 4th trick]?

DOES THIS MAKE SENSE?

IRISH
Last edited by irishwolf on Fri Jun 03, 2022 1:35 pm, edited 1 time in total.

irishwolf
Posts: 1273
Joined: Tue Apr 24, 2018 9:33 pm

Unread post by irishwolf » Fri Jun 03, 2022 12:41 am

RAY,

Let's for fun (bonus question) make your S1 defense a little tougher. Same hand for the Dealer. 2nd scenario. Dealer has the same hand, but change hands for S1 (see below). Should S1 lead the KH or the QD?

Give S1 QC 10C KH QD JD - now what should he lead?
ANSWER: Same as the above in 2. Why, because now he can only cover one card the 9C if Dealer has AC/9C or just the 9C. KH covers four heart singletons. QD/JD overs two lower cards and AD/10D or 9D.
Now S1 gets to signal on trick 2 telling S3 I am not saving Clubs.

----------------------------

Now to make it really tough, give S1 KC AD 9D AH 10H. I hate this hand defending because statistically you have two Ace stopping four cards, and a King (KC) that stops three cards. You should lead your Best stopper the AD. What makes this tough is do you Signal on trick two and toss the KC or save it to trick 4? Consider that you will confuse your partner with the 10H sloughing early! What if S3 has no stoppers in Clubs or Hearts? Will the Dealer have two low Clubs?

That is the predicament you are in.

If you lead the KC you will force yourself on trick 4 unless the dealer has a doubleton. Which is a better lead to the first trick?

I will let you mull this one over rather than giving my answer.

IRISH

Tbolt65
Posts: 795
Joined: Sun Jun 16, 2019 9:14 pm
Location: Las Vegas

Unread post by Tbolt65 » Wed Jun 08, 2022 1:46 am

raydog wrote:
Thu Jun 02, 2022 1:53 pm
I'm seeking the advice of the experts here, as I try to refine my euchre program.

Imagine S4 (dealer) is dealt A-10S + QH + J-9C, with JS turned.
[as an aside, do you prefer me listing the cards this way, or using the graphics?]

S4 calls alone in S. Should they discard the 9C or the QH? This is something I can't simulate, because the results are dependent on how I program S1 and S3 to play; so I introduce my own bias. I imagine this is situation dependent - playing against randos or know expert players - but I'd like to hear the verdict in either case.


Normally drop the 9c. If you have a read on lead preferences by seat 1, play accordingly.
_______________________



2nd scenario. Dealer has the same hand, and S1 is dealt Q-9S + KH + Q-JD. Should S1 lead the KH or the QD?
Personally I lead the opposite suit solo highest card from the up suit. In this case it would be the king of hearts.
And a corollary question: if I lead the QD and dealer wins with the AD, should I later discard the JD or the KH [this will likely be a decision to make on the 4th trick]? Would the answer change if I originally held the J-10, led the JD, and dealer won with the KD?
You should keep the other diamond because usually s4 will be two suited going alone. It's just a rule of thumb.

raydog
Posts: 238
Joined: Thu Sep 16, 2021 6:56 pm

Unread post by raydog » Mon Jun 20, 2022 3:23 pm

Very clear, Irish - thanks. Sorry it took me a while to respond, I tend to work on my euchre program in fits and spurts.

Now I need some more advice (from both you and others - but I know you approach these questions from the analytical/statistical standpoint which is important for me to create the best, unbiased algorithm.) I'm optimizing the play of loner hands, specifically what card S4 should discard if calling alone and what card S1 should land I'm having some issues because of the recursive nature of the problem. If S4, for example, bases her decision of what card to discard on pure statistics, S1 (knowing this) may alter their play to take this into account*.

So I am starting with the basics [and if this can be quantified, it will be a useful rule for all players]. Say S4 is calling alone; what card should they discard? Here are the rules I surmise are best - please opine:

S4 has 4 trump + 2 off-suit cards (before discarding)
1) 2xA or 2xK or 2xQ or 2xJ or 2x10 or 2x9, both green suits: toss-up [my program should use a randomizer to decide, so as not introduce a bias]
2) 2xA (green + next): keep the green A [less likely to be trumped if suit led by S1, first trick]
3) 2xK or 2xQ (green + next): keep the next suit [opponents are equally likely to have either A, but if one opponent has 2 or 3 Aces, they are more likely to save the green A if it comes down to that decision (it beats more cards). They are also more likely to prioritize a K-9 in a green suit over a K-9 in the next suit (should they have both), again from a statistical perspective.]
4) 2x10 or 2x9 (green + next): keep the next suit [more cards beat the green suit]
5) A + any x: keep the A [obvious]
6) 2 different ranks in 2 different suits: generally keep the higher ranking card
7) exception to 6) above: have 10 next and J green; each is beaten by 3 cards, but the opponent will keep green Q if deciding between green Q and next Q (singletons), and is also more likely to have a doubleton in a green suit and sacrifice, for example, a next Q to preserve a green Q-9 on the 3rd trick - should it come to that.

S4 has 3 trump + 3 off-suit cards (before discarding)
1) tripleton: discard lowest [obvious]
2) doubleton + singleton: discard singleton [unless singleton A, in which case discard lower doubleton card]
3) 3 singletons: discard worst card ["worst" based on how many cards it beats; in case of a tie, keep next suit]

Is this analysis reasonable? Am I missing anything?

* A basic analogy is 5-card draw poker w/ with wild cards. If you are dealt a natural pair plus a wild card, you will use the wild card to make 3-of-a-kind, which is worth more than 2-pair. But because you make this decision every time in this situation, 3-of-a-kind becomes more common than 2-pair, and so the hierarchy of hands should change...but then you would change your decision...

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