[Retros] Two little SPG-challenges

[Anders&Margareta]

For the record: Natch on P4 3 GHz 512 MB 
A: 1 mn 18.13 s
B: 10 mn 11.87 s
not a great diff 
/anders uddgren


----- Original Message ----- 
From: "Mario Richter" <mri_two at t-online.de>
To: <retros at janko.at>
Sent: Wednesday, November 10, 2004 2:39 PM
Subject: [Retros] Two little SPG-challenges



> Dear retro-friends,

> 

> maybe I can use the current low traffic on this

> mailing-list to present to you two little challenges.

> 

> While playing a little bit with the "At-Home-Proofgame"-

> theme, I found the following to positions:

> 

> Position A:

> 

> 

> +---+---+---+---+---+---+---+---+

> |*R |*S |*B | . |*K |*B |*S |*R |

> +---+---+---+---+---+---+---+---+

> |*P |*P | . |*P |*P |*P |*P |*P |

> +---+---+---+---+---+---+---+---+

> |   | . |   | . |   | . |   | . |

> +---+---+---+---+---+---+---+---+

> | . |   | . |   | . |   | . |   |

> +---+---+---+---+---+---+---+---+

> |   | . |   | . |   | . |   | . |

> +---+---+---+---+---+---+---+---+

> | . |   | . |   | . |   | . |   |

> +---+---+---+---+---+---+---+---+

> | P | P | P | P |   | P | P | P |

> +---+---+---+---+---+---+---+---+

> | R | S | . |   | K | B | S | R | (13 + 14)

> +---+---+---+---+---+---+---+---+

> 

> rnb1kbnr/pp1ppppp/8/8/8/8/PPPP1PPP/RN2KBNR

> 

> SPG in 7.5 moves

> 

> 

> Position B:

> 

> +---+---+---+---+---+---+---+---+

> |*R |*S |*B |*Q |*K | . |*S |*R |

> +---+---+---+---+---+---+---+---+

> |*P |*P |*P |*P |*P |*P | . |   |

> +---+---+---+---+---+---+---+---+

> |   | . |   | . |   | . |   | . |

> +---+---+---+---+---+---+---+---+

> | . |   | . |   | . |   | . |   |

> +---+---+---+---+---+---+---+---+

> |   | . |   | . |   | . |   | . |

> +---+---+---+---+---+---+---+---+

> | . |   | . |   | . |   | . |   |

> +---+---+---+---+---+---+---+---+

> | P | P | P | P | P | P | P | . |

> +---+---+---+---+---+---+---+---+

> | R |   | B | Q | K | B | . |   | (12 + 13)

> +---+---+---+---+---+---+---+---+

> 

> rnbqk1nr/pppppp2/8/8/8/8/PPPPPPP1/R1BQKB2

> 

> SPG in 7.0 moves

> 

> (If these problems are already published or

>  otherwise anticipated, I would be grateful,

>  if somebody could provide author and source.)

> 

> 

> First challenge:

> 

> Can you do better than 'natch' on a 350MHz-PII-machine?

> 

> (natch - with 128MB hash-table - solves 

>  - Pos A in  3min 50s

>  - Pos B in 34min 04s)

> 

> 

> If some of you try to solve the two problems,

> I would be grateful if you can send me your 

> solving times.

> 

> 

> Second challenge:

> 

> Both proof games contain a rather paradoxical

> element (at least I consider them that way).

> 

> Can you construct longer proof games (not

> necessarily of the "At-Home"-type), which show

> the same element?

> 

> 

>    greetings

>      mario

> 

> 

> 

> 

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