Can I get more details about reverse next?

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marya
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Can I get more details about reverse next?

Unread post by marya » Thu Jun 06, 2019 8:09 pm

Hi all,

I am trying to find out more about the tactic called "reverse next".

I see there are a couple of great examples here at Ohio Euchre:

https://ohioeuchre.com/E_What-Is-Reverse-Next-Call.php
https://ohioeuchre.com/E_What-Is-Reverse-Next-Call-example1.php

I believe I understand the basic principle. I'll reiterate what I understand:

1) Scores are low, so flubbing it won't be a disaster.
2) You're in 2nd chair, and your partner turned down the up card.
3) You have at least 9 and king in a suit whose color is opposite to the up card's suit. For example if the up card was 9 of hearts, then you hold perhaps tMaybe the thing that's got me a little confused is that I he 9 and king of clubs.
4) You only have 3 suits (maybe - I don't see this in the discussion at Ohio Euchre, but I did read this elsewhere).
5) You have an offsuit (non-trump) ace (maybe - in Ohio Euchre's second example above, there is no offsuit ace)

Okay, here are my questions:

A) Suppose you make a 'reverse next' call. The play described in the above links doesn't say what to do if you are void in the led suit. You've only got 2 trump cards. If you're void in the led suit and trump in, you'll only have one trump card left! Should you now lead with a card of the opposite color (assuming that is possible)? Should you lead with trump? Should you lead with a singleton suit? Should you lead with an offsuit ace, risking it might be trumped, if you've got one? What's the best exit strategy here?

B) Suppose you hold just the left and right bower in the suit that you're calling, and you've got a singleton ace. Is this technically a 'reverse next' call? I would think the same strategy applies, except that my cards are much stronger than the 9 and king. Is that correct? I just want to make sure that king and 9 are the minimum, and anything more than that is a definite "yes, call and play the reverse next strategy."

Basically, I sort of understand how the call works, but it's the strategy during the cardplay which has got me confused.

Marya



RedDuke
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Unread post by RedDuke » Thu Jun 06, 2019 8:50 pm

A) Suppose you make a 'reverse next' call. The play described in the above links doesn't say what to do if you are void in the led suit. You've only got 2 trump cards. If you're void in the led suit and trump in, you'll only have one trump card left! Should you now lead with a card of the opposite color (assuming that is possible)? Should you lead with trump? Should you lead with a singleton suit? Should you lead with an offsuit ace, risking it might be trumped, if you've got one? What's the best exit strategy here?
If the lead suit (that you're void in) is an ace then trump it. If it's something else, a green jack for example, then it depends. Usually I'll throw off something and see if my partner can take it. That's somewhat situational as it sort of depends what I've also got in my hand and what the suit is. If it's the suit that my partner as dealer turned down, then odds are he's also void and will be able to trump it himself.
B) Suppose you hold just the left and right bower in the suit that you're calling, and you've got a singleton ace. Is this technically a 'reverse next' call? I would think the same strategy applies, except that my cards are much stronger than the 9 and king. Is that correct? I just want to make sure that king and 9 are the minimum, and anything more than that is a definite "yes, call and play the reverse next strategy."
It's a reverse next call if the jacks are the opposite color from what the turn card was. If the dealer turned down the king of clubs and you call hearts while holding both red jacks then it is. In that case, it's a pretty easy call to make if your partner can get a trick (try to give them every opportunity by throwing off instead of trumping the first lead... unless the first lead is an ace).

It's a king-9 in the same suit and opposite color of the card that your partner (the dealer) turned down and at least one ace in some other suit. If you have better than a king-9 (say you have the jack-10) then it makes the call more likely to succeed. If you have three cards in the opposite color suit, then you're even better off, etc.

Example. You're holding this:

(Card_A-H) (Card_10-H) (Card_A-C) (Card_Q-D) (Card_10-D)

Your partner just turned down the (Card_Q-S) . You'll want to call hearts.

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marya
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Unread post by marya » Fri Jun 07, 2019 6:07 am

Super feedback RedDuke, thank you very much!

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marya
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Unread post by marya » Fri Jun 14, 2019 11:45 am

If anyone is curious, I ran some stats on "reverse next" to see if it really works (I admit, I was kind of skeptical). The page with the stats is here (sorry but you have to copy/paste the URL into your address bar if you want to take a look): https://worldofcardgames.com/euchre-card-game-reverse-next-strategy.html

The synopsis is that it does usually work, although it's actually pretty rare that you have the opportunity to use it!

Given that it seems to work, I'd use it even if the scores are not low. It goes wrong at times, but the success rate is good enough that I'd use it even when the game is close to ending.

RedDuke
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Unread post by RedDuke » Fri Jun 14, 2019 5:06 pm

marya wrote:
Fri Jun 14, 2019 11:45 am
If anyone is curious, I ran some stats on "reverse next" to see if it really works (I admit, I was kind of skeptical). The page with the stats is here (sorry but you have to copy/paste the URL into your address bar if you want to take a look): https://worldofcardgames.com/euchre-card-game-reverse-next-strategy.html

The synopsis is that it does usually work, although it's actually pretty rare that you have the opportunity to use it!

Given that it seems to work, I'd use it even if the scores are not low. It goes wrong at times, but the success rate is good enough that I'd use it even when the game is close to ending.
It becomes even more likely to work (as does a next call from first seat) if the card that the dealer turned down was something big. For example, if the dealer turned down a jack, it's a pretty good bet that they don't have anything good in that suit. It's also a sure bet that they don't have the other jack of the same color. Therefore, any good cards that they have are probably in reverse next.

If the dealer turned down a black nine, he might still be holding something like a pair of black kings though. Odds are pretty good that he's not holding a pair of black kings if he turned down an ace or a jack!

Catch10110
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Unread post by Catch10110 » Sat Jun 15, 2019 12:16 pm

marya wrote:
Fri Jun 14, 2019 11:45 am
If anyone is curious, I ran some stats on "reverse next" to see if it really works (I admit, I was kind of skeptical). The page with the stats is here (sorry but you have to copy/paste the URL into your address bar if you want to take a look): https://worldofcardgames.com/euchre-card-game-reverse-next-strategy.html

The synopsis is that it does usually work, although it's actually pretty rare that you have the opportunity to use it!

Given that it seems to work, I'd use it even if the scores are not low. It goes wrong at times, but the success rate is good enough that I'd use it even when the game is close to ending.
Nice write up! Love to see the numbers that go along with these types of things. How did you run the simulations? Is there anywhere online that you can do that? I would love to be able to do it, but i've never been able to find anything.

Richardb02
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Unread post by Richardb02 » Sat Jun 15, 2019 9:03 pm

Thank you mayra for sharing stats showing that Reverse-Next is a profitable concept from Seat 2.

Let me share a way of utilizing the Reverse-Next information into your bidding approach. It is found in my post, Bidding Point System - Basic.

It starts with evaluating your cards and combinations of cards.
1.00 Right

BPS assigns a value of 1.00 to the right.
It estimates the relative value of cards to the Right:
0.75 for the left
0.50 for AKQ trump
0.25 for T9 trump
It estimates the relative value of suits:
0.25 for a Void
0.75 for 2 Voids
0.50 for any 3 trump
0.75 for 3 trump with a Bower or 2
(There are more values in the post)
BPS then sets minimum total points to call:
2.00 is the minimum to call from Seat 2, for our Reverse-Next discussion.
Reverse-Next, is evaluated as well:
Add .50 for Seat 2 (the estimated benefit of being Dealer’s partner)
Add .25 for Round 2 (No player had a strong enough hand to call in Round 1)
Add 0.50 for a Reverse-Next call.
1.25 is the starting point for Seat 2, Round 2, Reverse-Next.
Add:
0.50 for K Trump
0.25 for 9 Trump
2.00 Total Points is the minimum to call (you have about a 2:1, 65% chance of winning the hand, with additional benefits, ie blocking an Alone)
If you also have a void:
+0.25 for a Void, so:
2.25 points, you now have. 72.5% chance to winning the hand.
If you have an Ace:
+0.50 for an Ace, so:
2.50 points and an 80% chance of success

It looks complicated, but it is easy and fast, with practice. It is based on and confirms Ohio Euchre lessons. BPS minimizes the guesswork of Calling. Sure there are other factors. The advanced players, on the OE Forum, point out other factors. But for anyone short of “advanced” status, IMO, it will improve their Euchre. It has improved mine!

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marya
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Unread post by marya » Sun Jun 16, 2019 8:20 am

RedDuke wrote:
Fri Jun 14, 2019 5:06 pm
It becomes even more likely to work (as does a next call from first seat) if the card that the dealer turned down was something big.
Hi RedDuke, Yes, for the stats that I ran, I only had my bots consider a "reverse next" strategy if the up card had been a jack or an ace. Anything lower, and the bot would not think about using that strategy. I understand the strategy can work when the up card is lower, but I thought this condition would be most likely to give it success.

If I made the conditions less strict, there would be more cases where it would be applicable, but I think we can be pretty sure that it would be less likely to be successful overall. Although, it might still be a success on average. I didn't run stats on that :)

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marya
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Unread post by marya » Sun Jun 16, 2019 8:44 am

Catch10110 wrote:
Sat Jun 15, 2019 12:16 pm
Nice write up! Love to see the numbers that go along with these types of things. How did you run the simulations? Is there anywhere online that you can do that? I would love to be able to do it, but i've never been able to find anything.
Hi Catch10110,

Thank you! I'm glad you liked it!

I run a website called World of Card Games where people can play Euchre (and other card games), against other people or against computer "bots".

The "bots" are basically computer models that decide how to choose and what to play based on some rules that are programmed into their code.

A friend of mine gave me the website in 2013. At the time, the bots only applied some very simple Euchre strategies. I kept getting emails from people complaining about how they worked - they did brain dead idiotic things, at times. So I added code to the site which would allow people to download a "hand history" after a hand finished. That way, people could "replay" the hand and see what cards were in everyone's hands and how everything was played. People could then send me the complete details of a hand and tell me what the bot did wrong, and give me an idea about what they should have done.

A few people helped out with numerous suggestions. I added quite a bit more bot strategy. At some point, no one sent me histories anymore... that doesn't mean the bots are any good, I think it just means they've been improved enough that people don't bother to email me. :)

So that's how the "bots" work. Because I've got the bot code available, I can use it to run numerous simulations. I wrote a test harness which set up 4 bots at a table, dealt the cards, displayed the up card, and the bots would use their code to decide how to choose. Then they'd play a hand according to their programming, and I'd record who "won" the hand (who got points). I set up the test harness to do this over a large number of hands so I'd get enough stats that it looked believable to me (I'm not a statistician, though!).

All this was done on my own development environment, a linux desktop.

Unfortunately, there's no way to do this online that I know about. As you can imagine, if the bots were programmed differently, the stats would not doubt come out differently. My bot code is proprietary. I have sometimes briefly thought about open sourcing the code, but I'm reluctant to do that. It's always been a goal of mine that World of Card Games would be a business that can support me, but it has not become that. It does give me a little income, though, from the on ad that is on the site. I'm reluctant to open source, and "show all my cards" to any competitors :)

If there were some serious demand to run experiments of this sort, I'd also consider making a separate site where this could be done.

Like you, I really enjoy running these types of experiments! But I suspect that we are a rare breed. If I did take the time to make a site where card games could be simulated, I suspect it would only get a few users. It would have to be a hobby site. I have nothing against that, but, unfortunately, there aren't enough hours in the day!

This reply is a bit long winded, but I hope it answers your questions :)

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marya
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Unread post by marya » Sun Jun 16, 2019 8:55 am

Richardb02 wrote:
Sat Jun 15, 2019 9:03 pm
Thank you mayra for sharing stats showing that Reverse-Next is a profitable concept from Seat 2.

Let me share a way of utilizing the Reverse-Next information into your bidding approach. It is found in my post, Bidding Point System - Basic.
Richardb02, Thank you for the information! Currently the bot code decides what to choose using an unsophisticated heuristic (supplemented by user feedback, which has helped!).

I don't have much time to spend on World of Card Games, right now. I had a little spare time, and got kind of carried away with the reverse-next stats :) But what I'll do is add it to my backlog to investigate your methodology and compare it to the current one. I expect your methodology will be an improvement. When I get the time, I will post in these forums, and hopefully get an improvement in the bot performance.

Wes (aka the legend)
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Unread post by Wes (aka the legend) » Tue Jun 18, 2019 3:03 pm

marya wrote:
Thu Jun 06, 2019 8:09 pm
3) You have at least 9 and king in a suit whose color is opposite to the up card's suit. For example if the up card was 9 of hearts, then you hold perhaps tMaybe the thing that's got me a little confused is that I he 9 and king of clubs.
Keep in mind that this suggestion is only meant as a rule of thumb for beginners, just like "never trump your partner's ace" and "count on your partner for one" are rule of thumbs for beginners. They're good rule of thumbs but they are far from perfect.

Playing the 2 seat, 2nd round spot well is certainly more than just focusing on your specific cards. For example, say your team is up 5-1, your partner the dealer turns down the (Card_Q-C) in the first round.

The action gets to you in the 2nd round and you have:

(Card_10-C) (Card_9-C) (Card_10-D) (Card_9-D) (Card_9-H)

Not calling diamonds in that spot would be criminal. You're up 5-1, you block nothing, you basically have nothing. With your holding you should be scared to death to hand the ball off to the 3rd seat. Call reverse next in diamonds and try to hit your partner instead. The 2nd round is about playing sound defense and trying to hit your partner. Never give 3rd seat the chance to be a hero in this spot. Protect your lead!

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marya
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Unread post by marya » Wed Jun 19, 2019 4:01 pm

Wes, wow that is very interesting - it would never occur to me to call with that hand. I think 90% of my partners would express extreme displeasure if I did that. But maybe I'm wrong :) I'd also be afraid to program my bots to do that, I think so many people would get out the pitchforks and torches ("how can your bot make a bid without a J!" etc). Definitely food for thought... I will try it when I have a forgiving partner.

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