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Old 03-15-2017, 11:07 AM   #26
Don Kament
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Re: Second best move is already a blunder.... Why?!

Here we go with Position 6:

White - Pips 162. Match Score 1/7

Black - Pips 157. Match Score 0/7
Black to Play 6-5
Created with www.BGdiagram.com

Heros move:
Spoiler:


Analysis:
Spoiler:
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Old 03-15-2017, 12:57 PM   #27
_Z_
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Re: Second best move is already a blunder.... Why?!

Haven't checked the spoilers yet.

This one seems tough to me. Can't totally rule out any of the legal 6s!

I'll with B/20* 8/2* mainly because it minimizes shots.
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Old 03-15-2017, 02:10 PM   #28
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Re: Second best move is already a blunder.... Why?!

Main issue with doing anything other than the double hit play is the risk of of him hitting & covering the 5 point (31 single hit, 33 double hit), and he can also double hit without covering (32,36), or cover the 5 point without hitting (55). Plus, there are significantly more bare single hit returns with any of the other plays, as well as the risk he can create a double anchor.
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Old 03-15-2017, 04:03 PM   #29
Don Kament
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Re: Second best move is already a blunder.... Why?!

Hi,

thanks for your answers. I spoiler some thought about the position, so that others might not be that much influenced if they don´t want to...

Spoiler:
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Old 03-15-2017, 05:13 PM   #30
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Re: Second best move is already a blunder.... Why?!

In the last position, as played, there are 27 return shots (any 3 (11 shots), any 6 except 66 (8 more shots), any 2 (7 more shots), and 11, of which 6 are double hits (11,33,32,36). With the best play, there are only 20 return shots (any 2 or 3), only 2 of which are double hits.
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Old 03-15-2017, 07:43 PM   #31
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Re: Second best move is already a blunder.... Why?!

Quote:
Originally Posted by snark View Post
In the last position, as played, there are 27 return shots (any 3 (11 shots), any 6 except 66 (8 more shots), any 2 (7 more shots), and 11, of which 6 are double hits (11,33,32,36). With the best play, there are only 20 return shots (any 2 or 3), only 2 of which are double hits.


Sorry it should've said 21 return shots in the best play, 3 of which are double hits (11 as well as 32).


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Old 03-15-2017, 11:34 PM   #32
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Re: Second best move is already a blunder.... Why?!

With a 54, 18/14 is safer than 20/14 was with a 65.

After 18/14, it's some 1s, 2s and 3s, plus some combo shots that hit you.
After 20/14, it's pretty much all 1s, 2s, 3s and 6s, plus 55.

With your 6 point made, you want to avoid giving your opponent a good hitting 6 when he's on the bar. That cuts down on the shots.
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Old 03-16-2017, 09:43 AM   #33
Robertie
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Re: Second best move is already a blunder.... Why?!

When your opponent has made an advanced anchor (in this case the 21-point), in general you don't want to be attacking behind the anchor in your board. It's a very good rule, and in this position I would have played Bar/20*/14 with 6-5 and Bar/20* 18/14 with 5-4.

Every now and then XG will come up with a play that's very counter-intuitive but is justified by the specific tactics of this position. Since I can't explain XG's play of 8/2* after 6-5, I'm guessing that's the case here. But 8/2* is so anti-positional (dumping a checker in the board when White has 4 men back and stripping the 8-point in the process) that I'd never find it over the board.
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Old 03-16-2017, 01:46 PM   #34
Don Kament
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Re: Second best move is already a blunder.... Why?!

Thanks - I love you guys! I really learn a lot about the game!

The next position should be easy for most of you.

Position 7:

White - Pips 151. Match Score 4/7

Black - Pips 170. Match Score 0/7
Black to Play 4-1
Created with www.BGdiagram.com

My move:
Spoiler:


Analysis:
Spoiler:
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Old 03-16-2017, 07:08 PM   #35
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Re: Second best move is already a blunder.... Why?!

(I'll always comment before looking at the spoilers)

I would hit 8/3*. It's not the greatest loose hit in the world because you're using your last spare to do it and that checker you're hitting isn't at the edge of the prime, but nothing else seems super-productive either. At least you're pushing White back a bit -- otherwise he can escape a checker with 6s.

The match score here helps the hit I believe.
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Old 03-17-2017, 06:10 AM   #36
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Re: Second best move is already a blunder.... Why?!

Although it is often wrong to slot the bar when the opponent has 4 men on their 8 point, I would slot here. The problem with hitting loose is that you diversify their numbers too much 2s, 3s, 4s and 6s hit a blot. You're also most likely going to concede a point of your 4 prime in order to cover. One of your main objectives right now is to make an advanced anchor. It is the wrong game plan to hit, and you definitely don't want to expose another man when you're down in the race and don't have an advanced anchor.

Now hitting a guy off the front of the prime (if the blot was on the 4 point) is a different theme: You can often keep your prime by rolling it forward when you cover. You would be slotting the point you most want to make, and the opponent's entry with a 6 is not as great (assuming you play the 1 from 24 to 23) their 44 doesn't play nearly as well either.
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Old 03-17-2017, 09:48 AM   #37
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Re: Second best move is already a blunder.... Why?!

You're right -- this one is easy. But first let's go back to Magriel's 'Safe Play v Bold Play' chapter and take another look at what he was talking about.

In Magriel's book, his examples of bold play were mostly about slotting the 5-point or not. If you slot and get away with it, you will make your best point and sometimes extend a prime. If you don't slot, the alternative is usually stacking or breaking a point somewhere. When your opponent has a weak board (with or without blots) you make the bold play. If he has a strong board, you play safe. In other words, you're looking at a position where making the bold play can result in a huge improvement in your position when it works.

That's not what we've got in this position. First of all, it's not clear what the bold play really is! Both 8/3* and 23/18 leaves the opponent plenty of shots, so we're really looking at two plays, each of which takes risks to improve the position. If there's a safe play here, it's 13/8, which I don't think anyone would make.

When looking at somewhat risky plays on both sides of the board, you should be asking yourself "Which play gives me the biggest upside if I get away with it?

If you play 8/3* and don't get hit, you'll be breaking either the 7-point or 8-point to cover it. That's going to represent a minor improvement in your front position.

If you play 23/18 and don't get hit, you've got a shot at making the 18-point anchor, which is a huge improvement on the other side of the board. There's also a variation where you get hit and then hit back, which gives you a slotted 18-point plus a big gain in the race. That's a lot more potential upside from 23/18.

There's some good stuff in Magriel's 'Safe v Bold' chapter, but it's also easily misapplied, as here.
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Old 03-18-2017, 10:57 AM   #38
Don Kament
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Re: Second best move is already a blunder.... Why?!

Thank you for your answers. It´s extremly helpful to read what and how you think about positions!

Let me ask a somewhat off topic question.

Do you have something like a routine when you try to figure out the best play?

I´m asking for it because when postition 7 came up, i remember that i did recognize that i have to break either the 7-point or 8-point to cover the blot, which is obviously bad, but i made the play anyway. I think that sometimes there is something like predefined idea/solution/habit in my head, which has a negative effect on the result.

Last edited by Don Kament; 03-18-2017 at 10:58 AM. Reason: wrong spelling
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Old 03-19-2017, 03:00 AM   #39
RolldUpTrips
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Re: Second best move is already a blunder.... Why?!

So I've read the thread/spoilers and know the move is wrong, but I want to sidetrack a bit, if that's okay, and discuss 23 and 9 in the last position. We already have 3 men back and a solid, but very flat, 4-prime. Meanwhile he currently has a direct number to escape. I feel like the upside of making the back is absolutely immense. While it really sucks to have him jump+hit, jumping is pretty bad for us already.

Having said all this, I already know that the play is going to be very wrong. I imagine there have to be not-too-dissimilar positions where it's right, though. I'm wondering if there might be some guidelines to tell the difference.
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Old 03-19-2017, 04:28 AM   #40
cboevey
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Re: Second best move is already a blunder.... Why?!

Quote:
Originally Posted by Don Kament View Post
Do you have something like a routine when you try to figure out the best play?
It depends on the position. But generally yes. Firstly, what is my game plan? How am I going to win? (e.g. I'm winning the race, so race and don't get into a blot hitting contest; I'm losing the race so I need to hit a blot; I've got a chance of priming a few men, I'm going to take some risk to extend my prime; If only I can escape the other back man, I'm a big favourite to get them home safely, so I'm going to run him now and hope he misses.

Sometimes the dice don't cooperative with your objectives and you are forced to make the least worst play. Other times you may be faced with a choice of good plays, but wouldn't understand which one is better.
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Old 03-21-2017, 01:44 PM   #41
Don Kament
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Re: Second best move is already a blunder.... Why?!

Quote:
Originally Posted by RolldUpTrips View Post
So I've read the thread/spoilers and know the move is wrong, but I want to sidetrack a bit, if that's okay, and discuss 23 and 9 in the last position. We already have 3 men back and a solid, but very flat, 4-prime. Meanwhile he currently has a direct number to escape. I feel like the upside of making the back is absolutely immense. While it really sucks to have him jump+hit, jumping is pretty bad for us already.

Having said all this, I already know that the play is going to be very wrong. I imagine there have to be not-too-dissimilar positions where it's right, though. I'm wondering if there might be some guidelines to tell the difference.
Hi, that´s a good question and hopefully someone with more experience and knowledge of the game will answer it. I played around with the position a bit to see when slotting the back of the prime seems to be important. The first idea was that the 15 shots (11 direct 6´s, 51 and 53) could be the main reason that the play is not an option. So i put the checker from the 3 to the 2 point.

White - Pips 152. Match Score 4/7

Black - Pips 170. Match Score 0/7
Black to Play 4-1
Created with www.BGdiagram.com

I would be quite happy with just -0,0183 equity loss, but slotting the opponents bar is still better...

to play 41

1. Rollout¹ 23/18 eq:+0,3136
Player: 53,60% (G:14,85% B:0,68%)
Opponent: 46,40% (G:17,93% B:2,76%)
Confidence: ±0,0144 (+0,2992..+0,3280) - [95,4%]
Duration: 2 minutes 03 seconds

2. Rollout¹ 24/23 13/9 eq:+0,2953 (-0,0183)
Player: 52,94% (G:15,52% B:0,79%)
Opponent: 47,06% (G:19,03% B:3,08%)
Confidence: ±0,0156 (+0,2798..+0,3109) - [4,6%]
Duration: 2 minutes 02 seconds

What happens, if my opponent also has a 4-point prime?

White - Pips 149. Match Score 4/7

Black - Pips 170. Match Score 0/7
Black to Play 4-1
Created with www.BGdiagram.com

to play 41

1. Rollout¹ 23/22 13/9 eq:-0,1891
Player: 41,88% (G:10,31% B:0,53%)
Opponent: 58,12% (G:25,76% B:5,59%)
Confidence: ±0,0168 (-0,2058..-0,1723) - [82,1%]
Duration: 1 minute 53 seconds

2. Rollout¹ 24/23 13/9 eq:-0,2001 (-0,0110)
Player: 40,82% (G:10,72% B:0,57%)
Opponent: 59,18% (G:24,71% B:3,83%)
Confidence: ±0,0155 (-0,2156..-0,1846) - [16,9%]
Duration: 2 minutes 01 second

3. Rollout¹ 8/3* eq:-0,2156 (-0,0265)
Player: 40,54% (G:10,85% B:0,50%)
Opponent: 59,46% (G:25,10% B:3,95%)
Confidence: ±0,0156 (-0,2312..-0,2000) - [0,5%]
Duration: 2 minutes 00 second

¹ 2592 Games rolled with Variance Reduction.
Moves: 2-ply, cube decisions: 3-ply Red

Ok, now it is better to slot the back of the prime, but i wouldn´t go that far to say that it does only matter in prime vs prime situations. I think it also depends on how important it is to extend the prime right now and how likely it is to extent the prime without slotting. Long story short - it depends.... Just kidding.

Well, XG says that my overall level is 11,49 - so i wouldn´t bet a house on my answer, but i would certainly bet my pants on it, since it´s always funny to see a guy playing backgammon without

Quote:
Originally Posted by cboevey View Post
It depends on the position. But generally yes. Firstly, what is my game plan? How am I going to win? (e.g. I'm winning the race, so race and don't get into a blot hitting contest; I'm losing the race so I need to hit a blot; I've got a chance of priming a few men, I'm going to take some risk to extend my prime; If only I can escape the other back man, I'm a big favourite to get them home safely, so I'm going to run him now and hope he misses.

Sometimes the dice don't cooperative with your objectives and you are forced to make the least worst play. Other times you may be faced with a choice of good plays, but wouldn't understand which one is better.
Thanks, i´ll give it a go. I still make blunders because i either missed a play or chose the wrong game plan. It seems like that i almost stop thinking when i see the first "good looking" play.
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Old 03-21-2017, 05:22 PM   #42
Robertie
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Re: Second best move is already a blunder.... Why?!

The 'game plan' idea is much overused. You want to make the play that improves your overall position the most. That might be an offensive play, or it might be a defensive play.

In the position we're discussing, I honestly wouldn't have a 'game plan' over the board, because the position still hasn't taken on a defined shape. I'd roll the dice and then see if the roll improves my front position, and by how much, and then I'd look to see if it improves my back position, and by how much. Once I look at the position that way, I notice that 4-1 doesn't do much for my front game whether I play 13/8 or 13/9 24/23 or 8/3*. But 23/18 is a huge improvement of my back checkers, so that's my play.

The other problem with the 'game plan' sort of thinking is that it will often cause you to overlook plays that are unusual but which fit the specific roll and position very well. Simply overlooking plays altogether is one of the most common sources of error.
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Old 04-02-2017, 04:12 AM   #43
Don Kament
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Re: Second best move is already a blunder.... Why?!

Hi,
after a short break from backgammon, i´m back in business with the following position. It should be easy for most of you, but since i still make mistakes in that kind of position, i like to post it.

Position 8:

White - Pips 134. Match Score 0/7

Black - Pips 149. Match Score 0/7
Black to Play 5-4
Created with www.BGdiagram.com

My move:
Spoiler:


Analysis:
Spoiler:


Again, if someone else likes to post a position, feel free to post it!
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Old 04-02-2017, 09:23 AM   #44
Robertie
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Re: Second best move is already a blunder.... Why?!

I'm going to split here (24/20 13/8) for all the obvious reasons: I have a stronger board, I want an advanced anchor, I want to prevent White from dropping builders in his outer board, etc. White has few pointing numbers, and on some of them (21, 32) I get plenty of return shots.

If you think it's too dangerous to split here, when do you plan to split?
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Old 04-03-2017, 10:53 AM   #45
_Z_
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Re: Second best move is already a blunder.... Why?!

You should provoke contact with 13/8 24/20. Certainly you'll hit White next turn more often with that play than any other.

It also threatens to make an advanced anchor, which is nice, though it's conceivable you'll sometimes choose to remain split next turn.

There's some risk of being attacked, but it's worth it. And I don't think it's close. Note you outboard White 3 to 1.
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Old 04-27-2017, 03:57 AM   #46
Don Kament
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Re: Second best move is already a blunder.... Why?!

Hi folks,

thanks for your input on the previous postion.
I´m back from holidays , means i´m back in backgammon business

Position 9:

White - Pips 147. Match Score 6/11

Black - Pips 141. Match Score 0/11
Black to Play 5-4
Created with www.BGdiagram.com

My move:
Spoiler:


Analysis:
Spoiler:
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Old 04-27-2017, 04:30 AM   #47
Don Kament
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Re: Second best move is already a blunder.... Why?!

Let´s post another one.

Position 10:

White - Pips 113. Match Score 6/11

Black - Pips 125. Match Score 0/11
Black to Play 4-1
Created with www.BGdiagram.com

My move:
Spoiler:


Analysis:
Spoiler:
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Old 04-28-2017, 05:36 AM   #48
RolldUpTrips
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Re: Second best move is already a blunder.... Why?!

Posting without spoilers:

First one the natural 3 and 20 should be right. The other candidates seem to be 3 and 1 and 8 and 3, but neither accomplishes as much as the split does. It will be VERY hard for white to attack your split being so outboarded - he will actually have to point on you. In the meantime you pressure his blot on the 9 and guard his outfield making it hard for him to build. Trying to attack immediately seems to be an overplay with so few builders and only 10 in the zone, while a tempo hit is not so important with no split to protect or anything like that. As far as the third play, the 8 isn't so important once you've made the 2, so the split seems a much bigger improvement.

Second position I really only see one play - 21 and 5*. Anything else exposes extra blots anyway so you might as well put him in the air with your better board and have your spare poised to escape and control the outfield.
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Old 04-28-2017, 05:38 AM   #49
RolldUpTrips
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Re: Second best move is already a blunder.... Why?!

Ok looked at the spoilers. No further comment on #1 but on #2 seeing a board get broken like that pains my heart :-(

In general (based on two positions, at any rate), seems that you don't weigh board strength (both relative and absolute) enough as a factor when choosing your plays.
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Old 04-29-2017, 01:45 PM   #50
Don Kament
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Re: Second best move is already a blunder.... Why?!

Quote:
Originally Posted by RolldUpTrips View Post
Ok looked at the spoilers. No further comment on #1 but on #2 seeing a board get broken like that pains my heart :-(

In general (based on two positions, at any rate), seems that you don't weigh board strength (both relative and absolute) enough as a factor when choosing your plays.
You´re absolutly right. Currently the most errors i make, come from overlooking plays. Even though i remind myself to take my time before a match, it still happens....

Thanks for your input!
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