XGID=---B-EEB----A--------ad---:1:1:1:22:0:0:0:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| | | O O |
| | | O |
| | | O |
| | | O |
| | | |
| |BAR| |
| | | X X |
| | | X X |
| | | X X | +---+
| X | | X X X | | 2 |
| X X | | X X X | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 87 O: 16 X-O: 0-0
Cube: 2, X own cube
X to play 22

---
Tim Chow

On Tuesday, April 5, 2022 at 1:57:40 PM UTC+1, Tim Chow wrote:
> XGID=---B-EEB----A--------ad---:1:1:1:22:0:0:0:0:10
>
> X:Player 1 O:Player 2
> Score is X:0 O:0. Unlimited Game
> +13-14-15-16-17-18------19-20-21-22-23-24-+
> | | | O O |
> | | | O |
> | | | O |
> | | | O |
> | | | |
> | |BAR| |
> | | | X X |
> | | | X X |
> | | | X X | +---+
> | X | | X X X | | 2 |
> | X X | | X X X | +---+
> +12-11-10--9--8--7-------6--5--4--3--2--1-+
> Pip count X: 87 O: 16 X-O: 0-0
> Cube: 2, X own cube
> X to play 22
>
> ---
> Tim Chow

Perhaps not the hardest Gruntyization you've ever set.
I think a good strategy is to maximise our probability of bearing off in two.
(In other words, bearing off on the next roll after this 22).

12/6 7/5 definitely comes into consideration. This gives us a gammon save with any 6, 5 or 3 -- 27.
We can also add the two Gruntyizations -- 11 and 22 for a 29/36 probability.

That might be tough to beat.

It looks to me like any other play will give a bad ace. So I'm sticking with my 29/36 problem.
So what's the moral of this story?

It's better to Gruntyize than to temporise -- that's my lesson learned.

Paul

On Tuesday, April 5, 2022 at 7:21:59 PM UTC+1, peps...@gmail.com wrote:
> On Tuesday, April 5, 2022 at 1:57:40 PM UTC+1, Tim Chow wrote:
> > XGID=---B-EEB----A--------ad---:1:1:1:22:0:0:0:0:10
> >
> > X:Player 1 O:Player 2
> > Score is X:0 O:0. Unlimited Game
> > +13-14-15-16-17-18------19-20-21-22-23-24-+
> > | | | O O |
> > | | | O |
> > | | | O |
> > | | | O |
> > | | | |
> > | |BAR| |
> > | | | X X |
> > | | | X X |
> > | | | X X | +---+
> > | X | | X X X | | 2 |
> > | X X | | X X X | +---+
> > +12-11-10--9--8--7-------6--5--4--3--2--1-+
> > Pip count X: 87 O: 16 X-O: 0-0
> > Cube: 2, X own cube
> > X to play 22
> >
> > ---
> > Tim Chow
> Perhaps not the hardest Gruntyization you've ever set.
> I think a good strategy is to maximise our probability of bearing off in two.
> (In other words, bearing off on the next roll after this 22).
>
> 12/6 7/5 definitely comes into consideration. This gives us a gammon save with any 6, 5 or 3 -- 27.
> We can also add the two Gruntyizations -- 11 and 22 for a 29/36 probability.
>
> That might be tough to beat.
>
> It looks to me like any other play will give a bad ace. So I'm sticking with my 29/36 problem.
> So what's the moral of this story?
>
> It's better to Gruntyize than to temporise -- that's my lesson learned.
>
> Paul

I mean "29/36 probability" (not problem).

Paul

On Tuesday, April 5, 2022 at 7:23:40 PM UTC+1, peps...@gmail.com wrote:
> On Tuesday, April 5, 2022 at 7:21:59 PM UTC+1, peps...@gmail.com wrote:
> > On Tuesday, April 5, 2022 at 1:57:40 PM UTC+1, Tim Chow wrote:
> > > XGID=---B-EEB----A--------ad---:1:1:1:22:0:0:0:0:10
> > >
> > > X:Player 1 O:Player 2
> > > Score is X:0 O:0. Unlimited Game
> > > +13-14-15-16-17-18------19-20-21-22-23-24-+
> > > | | | O O |
> > > | | | O |
> > > | | | O |
> > > | | | O |
> > > | | | |
> > > | |BAR| |
> > > | | | X X |
> > > | | | X X |
> > > | | | X X | +---+
> > > | X | | X X X | | 2 |
> > > | X X | | X X X | +---+
> > > +12-11-10--9--8--7-------6--5--4--3--2--1-+
> > > Pip count X: 87 O: 16 X-O: 0-0
> > > Cube: 2, X own cube
> > > X to play 22
> > >
> > > ---
> > > Tim Chow
> > Perhaps not the hardest Gruntyization you've ever set.
> > I think a good strategy is to maximise our probability of bearing off in two.
> > (In other words, bearing off on the next roll after this 22).
> >
> > 12/6 7/5 definitely comes into consideration. This gives us a gammon save with any 6, 5 or 3 -- 27.
> > We can also add the two Gruntyizations -- 11 and 22 for a 29/36 probability.
> >
> > That might be tough to beat.
> >
> > It looks to me like any other play will give a bad ace. So I'm sticking with my 29/36 problem.
> > So what's the moral of this story?
> >
> > It's better to Gruntyize than to temporise -- that's my lesson learned.
> >
> > Paul
> I mean "29/36 probability" (not problem).
>
> Paul
A riddle:
How long does it take to resolve a Gruntyization?
At least four days.

Paul

XGID=---B-EEB----A--------ad---:1:1:1:22:0:0:0:0:10

X:Player 1 O:Player 2
Score is X:0 O:0. Unlimited Game
+13-14-15-16-17-18------19-20-21-22-23-24-+
| | | O O |
| | | O |
| | | O |
| | | O |
| | | |
| |BAR| |
| | | X X |
| | | X X |
| | | X X | +---+
| X | | X X X | | 2 |
| X X | | X X X | +---+
+12-11-10--9--8--7-------6--5--4--3--2--1-+
Pip count X: 87 O: 16 X-O: 0-0
Cube: 2, X own cube
X to play 22

In "John Nunn's Chess Puzzle Book," he has a section called, "Find
the Wrong Move." Unlike most puzzles, in which the goal is to find
the right move, the goal in these puzzles is to guess what plausible
but wrong move was made OTB.

Here, the "obvious" 12/6 7/5 is correct. But somehow I fixated on
the gap on my 4pt, and played 12/8 7/5(2) to give myself a good 4.
It's true that after 12/6 7/5, I could roll 44 several times in a
row and get gammoned, but this is a rare event, and guarding against
a bad ace is a higher priority.

1. Rollout¹ 12/6 7/5 eq:-1.041
Player: 0.00% (G:0.00% B:0.00%)
Opponent: 100.00% (G:4.06% B:0.00%)
Confidence: ±0.000 (-1.041..-1.041) - [100.0%]

2. Rollout¹ 12/8 7/5(2) eq:-1.075 (-0.034)
Player: 0.00% (G:0.00% B:0.00%)
Opponent: 100.00% (G:7.46% B:0.00%)
Confidence: ±0.000 (-1.075..-1.075) - [0.0%]

3. Rollout¹ 12/10 7/5(2) 3/1 eq:-1.086 (-0.046)
Player: 0.00% (G:0.00% B:0.00%)
Opponent: 100.00% (G:8.65% B:0.00%)
Confidence: ±0.000 (-1.087..-1.086) - [0.0%]

¹ 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves and cube decisions: XG Roller++
Search interval: Gigantic

eXtreme Gammon Version: 2.19.207.pre-release

---
Tim Chow

On Thursday, April 14, 2022 at 1:19:41 PM UTC+1, Tim Chow wrote:
> XGID=---B-EEB----A--------ad---:1:1:1:22:0:0:0:0:10
>
> X:Player 1 O:Player 2
> Score is X:0 O:0. Unlimited Game
> +13-14-15-16-17-18------19-20-21-22-23-24-+
> | | | O O |
> | | | O |
> | | | O |
> | | | O |
> | | | |
> | |BAR| |
> | | | X X |
> | | | X X |
> | | | X X | +---+
> | X | | X X X | | 2 |
> | X X | | X X X | +---+
> +12-11-10--9--8--7-------6--5--4--3--2--1-+
> Pip count X: 87 O: 16 X-O: 0-0
> Cube: 2, X own cube
> X to play 22
> In "John Nunn's Chess Puzzle Book," he has a section called, "Find
> the Wrong Move." Unlike most puzzles, in which the goal is to find
> the right move, the goal in these puzzles is to guess what plausible
> but wrong move was made OTB.
In my experience, this is a very common concept in chess writing.
David Smerdon discusses it in a book on swindling, and Gary Lane, too, in another book.
And I've seen many problems in newspaper or magazine articles with exactly the
same goal. However, usually, these problems are presented as a dual:
A) Find the wrong move. B) Find the way your opponent should reply if you do make the wrong move.
In fact, a non-dual which focused solely on A without B seems a bit implausible.
And not really possible. If you don't do B, you can't explain why your answer to A is indeed wrong.
It's possible that John Nunn popularised the concept, I suppose.

> Here, the "obvious" 12/6 7/5 is correct. But somehow I fixated on
> the gap on my 4pt, and played 12/8 7/5(2) to give myself a good 4.
> It's true that after 12/6 7/5, I could roll 44 several times in a
> row and get gammoned, but this is a rare event, and guarding against
> a bad ace is a higher priority.
>
> 1. Rollout¹ 12/6 7/5 eq:-1.041
> Player: 0.00% (G:0.00% B:0.00%)
> Opponent: 100.00% (G:4.06% B:0.00%)
> Confidence: ±0.000 (-1.041..-1.041) - [100.0%]
>
> 2. Rollout¹ 12/8 7/5(2) eq:-1.075 (-0.034)
> Player: 0.00% (G:0.00% B:0.00%)
> Opponent: 100.00% (G:7.46% B:0.00%)
> Confidence: ±0.000 (-1.075..-1.075) - [0.0%]
>
> 3. Rollout¹ 12/10 7/5(2) 3/1 eq:-1.086 (-0.046)
> Player: 0.00% (G:0.00% B:0.00%)
> Opponent: 100.00% (G:8.65% B:0.00%)
> Confidence: ±0.000 (-1.087..-1.086) - [0.0%]
>
> ¹ 1296 Games rolled with Variance Reduction.
> Dice Seed: 271828
> Moves and cube decisions: XG Roller++
> Search interval: Gigantic
>
> eXtreme Gammon Version: 2.19.207.pre-release

You were lucky to only lose 0.34 equity. It looked worse than that to me.

Paul

On 4/14/2022 2:08 PM, peps...@gmail.com wrote:
> And I've seen many problems in newspaper or magazine articles with exactly the
> same goal. However, usually, these problems are presented as a dual:
> A) Find the wrong move. B) Find the way your opponent should reply if you do make the wrong move.
> In fact, a non-dual which focused solely on A without B seems a bit implausible.
> And not really possible. If you don't do B, you can't explain why your answer to A is indeed wrong.

Yes, that's what Nunn asks the reader to do.

> It's possible that John Nunn popularised the concept, I suppose.

He wrote his book in 1999.

---
Tim Chow

On Saturday, April 16, 2022 at 3:59:10 AM UTC+1, Tim Chow wrote:
> On 4/14/2022 2:08 PM, peps...@gmail.com wrote:
> > And I've seen many problems in newspaper or magazine articles with exactly the
> > same goal. However, usually, these problems are presented as a dual:
> > A) Find the wrong move. B) Find the way your opponent should reply if you do make the wrong move.
> > In fact, a non-dual which focused solely on A without B seems a bit implausible.
> > And not really possible. If you don't do B, you can't explain why your answer to A is indeed wrong.
> Yes, that's what Nunn asks the reader to do.

And there are also tasks that the reader asks Nunn to do (at least one reader, anyway).
1) Write a book on Q + P vs Q endings -- the lack of such a book is a marked gap in his
series on five-piece endings.

2) Write a book on selfmates -- someone needs to.

Paul

On 4/16/2022 4:21 AM, peps...@gmail.com wrote:
> And there are also tasks that the reader asks Nunn to do (at least one reader, anyway).
> 1) Write a book on Q + P vs Q endings -- the lack of such a book is a marked gap in his
> series on five-piece endings.

Interesting. I was vaguely aware of this series of books, but did
not realize that he never wrote "Secrets of Queen Endings."

> 2) Write a book on selfmates -- someone needs to.

These do exist, but they are not widely advertised, so you may need
to seek out someone in the chess problem community to get a list. One
book that is relatively easy to obtain is "The Art of Composing
Selfmates" by Petko A. Petkov. I think you can buy it from here:

http://www.strategems.net/shop/shop.html

---
Tim Chow

On Thursday, April 14, 2022 at 8:19:41 AM UTC-4, Tim Chow wrote:
> XGID=---B-EEB----A--------ad---:1:1:1:22:0:0:0:0:10
>
> X:Player 1 O:Player 2
> Score is X:0 O:0. Unlimited Game
> +13-14-15-16-17-18------19-20-21-22-23-24-+
> | | | O O |
> | | | O |
> | | | O |
> | | | O |
> | | | |
> | |BAR| |
> | | | X X |
> | | | X X |
> | | | X X | +---+
> | X | | X X X | | 2 |
> | X X | | X X X | +---+
> +12-11-10--9--8--7-------6--5--4--3--2--1-+
> Pip count X: 87 O: 16 X-O: 0-0
> Cube: 2, X own cube
> X to play 22
> In "John Nunn's Chess Puzzle Book," he has a section called, "Find
> the Wrong Move." Unlike most puzzles, in which the goal is to find
> the right move, the goal in these puzzles is to guess what plausible
> but wrong move was made OTB.
>
> Here, the "obvious" 12/6 7/5 is correct. But somehow I fixated on
> the gap on my 4pt, and played 12/8 7/5(2) to give myself a good 4.
> It's true that after 12/6 7/5, I could roll 44 several times in a
> row and get gammoned, but this is a rare event, and guarding against
> a bad ace is a higher priority.
>
> 1. Rollout¹ 12/6 7/5 eq:-1.041
> Player: 0.00% (G:0.00% B:0.00%)
> Opponent: 100.00% (G:4.06% B:0.00%)
> Confidence: ±0.000 (-1.041..-1.041) - [100.0%]
>
> 2. Rollout¹ 12/8 7/5(2) eq:-1.075 (-0.034)
> Player: 0.00% (G:0.00% B:0.00%)
> Opponent: 100.00% (G:7.46% B:0.00%)
> Confidence: ±0.000 (-1.075..-1.075) - [0.0%]
>
> 3. Rollout¹ 12/10 7/5(2) 3/1 eq:-1.086 (-0.046)
> Player: 0.00% (G:0.00% B:0.00%)
> Opponent: 100.00% (G:8.65% B:0.00%)
> Confidence: ±0.000 (-1.087..-1.086) - [0.0%]
>
> ¹ 1296 Games rolled with Variance Reduction.
> Dice Seed: 271828
> Moves and cube decisions: XG Roller++
> Search interval: Gigantic
>
> eXtreme Gammon Version: 2.19.207.pre-release
>
> ---
> Tim Chow

I have a collection of these (near) last roll should be obvious but people can still mess them up save the gammon type problems.

Stick