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 Post subject: Re: Retrograde problems
PostPosted: Sun Aug 19, 2018 10:46 
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Joined: Thu Apr 26, 2007 18:51
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Location: FRANCE
ildjarn wrote:
#7, first attempt:
Spoiler:
21, 27, 37, 47, 48, 49 / 4, 11, 12, 14, 24, 33, 38, 39, 43; 1. 21-16 39-44 2. 16x18 38-42 3. 47x9 4x42


Congratualation Joost because such problem are not really easy!
Your score is 061000. By using your idea in the other direction you can reach the 060900 optimum score
Spoiler:
Image

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Gérard


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 Post subject: Re: Retrograde problems
PostPosted: Sun Aug 19, 2018 12:34 
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Real name: Joost de Heer
First idea for #6, not correct since there are several possibilities, but perhaps you can indicate whether I'm searching in the right direction? Or does 'you are not allowed to use kings' also apply to the solution?

Spoiler:
8, 39, 47, 48 / 11, 17, 22, 24, 25, 37, 38, 42; 1. 8-2 37-41 2. 2x49 22-27 3. 49x30 25x43.

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 Post subject: Re: Retrograde problems
PostPosted: Sun Aug 19, 2018 14:14 
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Real name: Joost de Heer
Second idea for 6
Spoiler:
20 21 26 30 47 48 / 3 11 12 13 31 32 33 37 38
1. 21-16 37-41 2. 26×39 38-42 3. 16×9 3×43

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Lasst die Maschinen verhungern, Ihr Narren...

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!


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 Post subject: Re: Retrograde problems
PostPosted: Sun Aug 19, 2018 14:46 
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Joined: Thu Apr 26, 2007 18:51
Posts: 950
Location: FRANCE
ildjarn wrote:
First idea for #6, not correct since there are several possibilities, but perhaps you can indicate whether I'm searching in the right direction? Or does 'you are not allowed to use kings' also apply to the solution?

Spoiler:
8, 39, 47, 48 / 11, 17, 22, 24, 25, 37, 38, 42; 1. 8-2 37-41 2. 2x49 22-27 3. 49x30 25x43.


The best solution with kings is the following (score = 030602)
Image
1...38-27 2.31x28 23x41
but effectively I asked four the ten diagrams to avoid using kings

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Gérard


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 Post subject: Re: Retrograde problems
PostPosted: Sun Aug 19, 2018 14:59 
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Joined: Thu Apr 26, 2007 18:51
Posts: 950
Location: FRANCE
ildjarn wrote:
Second idea for 6
Spoiler:
20 21 26 30 47 48 / 3 11 12 13 31 32 33 37 38
1. 21-16 37-41 2. 26×39 38-42 3. 16×9 3×43


Your score (061000) is almost optimum.
You can reach the 051000

Spoiler:
Image
1...37-42 2.26x39 27-31 3.36x9 3x49


For your information, with 6 plies you can reach 060600
Image
1.45-40 26-31 2.36x38 39-43 3.50x39 35x42

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Gérard


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 Post subject: Re: Retrograde problems
PostPosted: Mon Aug 20, 2018 17:11 
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Joined: Tue Aug 22, 2006 15:38
Posts: 1439
Real name: Joost de Heer
#9:

Spoiler:
25 32 40 43 44 45 / 8 9 14 16 17 20 29 30 34
1. 40-35 34-40 2. 45x23 14-19 3. 23x21 16x40

_________________
Lasst die Maschinen verhungern, Ihr Narren...

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!


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 Post subject: Re: Retrograde problems
PostPosted: Mon Aug 20, 2018 17:49 
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Location: FRANCE
ildjarn wrote:
#9:

Spoiler:
25 32 40 43 44 45 / 8 9 14 16 17 20 29 30 34
1. 40-35 34-40 2. 45x23 14-19 3. 23x21 16x40


Very good Joost it is the optimum! Congratulations.

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Gérard


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 Post subject: Re: Retrograde problems
PostPosted: Sat Aug 25, 2018 18:58 
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Joined: Tue Aug 22, 2006 15:38
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Real name: Joost de Heer
I finally found something for #8, but since it's 7 moves long I know it's not optimal.

Spoiler:
6, 9, 26, 28, 36, 47 / 11, 12, 17, 24, 25, 27, 34, 37, 41, 43, 44
1... 17-22 2. 28x8 27-31 3. 6x17 37-42 4. 47x20 25x21

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Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!


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 Post subject: Re: Retrograde problems
PostPosted: Sat Aug 25, 2018 19:39 
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Joined: Thu Apr 26, 2007 18:51
Posts: 950
Location: FRANCE
ildjarn wrote:
I finally found something for #8, but since it's 7 moves long I know it's not optimal.

Spoiler:
6, 9, 26, 28, 36, 47 / 11, 12, 17, 24, 25, 27, 34, 37, 41, 43, 44
1... 17-22 2. 28x8 27-31 3. 6x17 37-42 4. 47x20 25x21


Very good start, you are not very far from the optimum (060900).

Instead of starting from the position
Image

try the following one
Image

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Gérard


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 Post subject: Re: Retrograde problems
PostPosted: Sat Aug 25, 2018 23:16 
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Joined: Tue Aug 22, 2006 15:38
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Real name: Joost de Heer
Spoiler:
8, 9, 26, 36, 42, 47 / 22, 24, 25, 27, 32, 33, 38, 41
1. 42-37 27-31 2. 37x17 38-42 3. 47x20 25x21

_________________
Lasst die Maschinen verhungern, Ihr Narren...

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!


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 Post subject: Re: Retrograde problems
PostPosted: Sun Aug 26, 2018 12:51 
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Joined: Thu Apr 26, 2007 18:51
Posts: 950
Location: FRANCE
ildjarn wrote:
Spoiler:
8, 9, 26, 36, 42, 47 / 22, 24, 25, 27, 32, 33, 38, 41
1. 42-37 27-31 2. 37x17 38-42 3. 47x20 25x21


Yes Joost it is THE solution
Congratulations

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Gérard


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 Post subject: Re: Retrograde problems
PostPosted: Sun Aug 26, 2018 13:46 
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Joined: Tue Aug 22, 2006 15:38
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Real name: Joost de Heer
That only leaves #10, but I doubt I can solve that one.

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Lasst die Maschinen verhungern, Ihr Narren...

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!


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 Post subject: Re: Retrograde problems
PostPosted: Sun Aug 26, 2018 16:00 
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Posts: 950
Location: FRANCE
ildjarn wrote:
That only leaves #10, but I doubt I can solve that one.


Yes Joost the #10 problem is very difficult if you are not allowed to use kings.

By the way and with more experience I change the way to calculate the score because I do not like to calculate the number of kings and get a negative number and in addition it does not give a good indication of the dfficulty of the problem.
Instead of comparing the intial and the final position I am now convinced that it is far better to consider only the pieces captured.

My new proposal for calculating the score is the following:

pliesNumber = total number of plies
piecesAddedNumber = total number of pieces captured
kingsAddedNumber = total number of kings captured
score = (10000 * pliesNumber) + (100 * piecesAddedNumber) + kingsAddedNumber

To come back to #10 problem you can try to solve it with kings allowed. Yhe optimal score is 03 06 02

Solution of #10 problem when kings are not allowed
Spoiler:
Image
20-14 33-39 44x42 34-39 49x9 4x13 35x33 13-18 14x21 16x20

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Gérard


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 Post subject: Re: Retrograde problems
PostPosted: Sun Aug 26, 2018 17:05 
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Joined: Tue Aug 22, 2006 15:38
Posts: 1439
Real name: Joost de Heer
Yes, with kings it's easy, 24-13 9×23 28×10

_________________
Lasst die Maschinen verhungern, Ihr Narren...

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!


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 Post subject: Re: Retrograde problems
PostPosted: Sun Aug 26, 2018 19:18 
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Joined: Thu Apr 26, 2007 18:51
Posts: 950
Location: FRANCE
Hi Joost,

I would like to show you a very exceptionnal position

Image

Though it is not easy you can try to find the solution with the best score which is 070702.

What is exceptionnal in this position is the solution if you are not allowed to use kings. In this hypothesis the problem is absolutely terrific. Do not take to much time on it because it is out of the scope of humans. I will show you the solution in my next post in order for you to first appreciate the difficulty.

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Gérard


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