## Retrograde problems

### Re: Retrograde problems

Congratualation Joost because such problem are not really easy!ildjarn wrote:#7, first attempt:Spoiler:

Your score is 061000. By using your idea in the other direction you can reach the 060900 optimum score

**Spoiler:**

Gérard

### Re: Retrograde problems

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:**

Lasst die Maschinen verhungern, Ihr Narren...

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

### Re: Retrograde problems

Second idea for 6

**Spoiler:**

Lasst die Maschinen verhungern, Ihr Narren...

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

### Re: Retrograde problems

The best solution with kings is the following (score = 030602)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:

1...38-27 2.31x28 23x41

but effectively I asked four the ten diagrams to avoid using kings

Gérard

### Re: Retrograde problems

Your score (061000) is almost optimum.ildjarn wrote:Second idea for 6Spoiler:

You can reach the 051000

**Spoiler:**

1.45-40 26-31 2.36x38 39-43 3.50x39 35x42

Gérard

### Re: Retrograde problems

#9:

**Spoiler:**

Lasst die Maschinen verhungern, Ihr Narren...

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

### Re: Retrograde problems

Very good Joost it is the optimum! Congratulations.ildjarn wrote:#9:

Spoiler:

Gérard

### Re: Retrograde problems

I finally found something for #8, but since it's 7 moves long I know it's not optimal.

**Spoiler:**

Lasst die Maschinen verhungern, Ihr Narren...

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

### Re: Retrograde problems

Very good start, you are not very far from the optimum (060900).ildjarn wrote:I finally found something for #8, but since it's 7 moves long I know it's not optimal.

Spoiler:

Instead of starting from the position

try the following one

Gérard

### Re: Retrograde problems

**Spoiler:**

Lasst die Maschinen verhungern, Ihr Narren...

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

### Re: Retrograde problems

That only leaves #10, but I doubt I can solve that one.

Lasst die Maschinen verhungern, Ihr Narren...

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

### Re: Retrograde problems

Yes Joost the #10 problem is very difficult if you are not allowed to use kings.ildjarn wrote:That only leaves #10, but I doubt I can solve that one.

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:**

Gérard

### Re: Retrograde problems

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!

Lasst sie verrecken!

Schlagt sie tot -- die Maschinen!

### Re: Retrograde problems

Hi Joost,

I would like to show you a very exceptionnal position

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.

I would like to show you a very exceptionnal position

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.

Gérard