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Subject: Re: Mate to solve for champions...

Author: Heiner Marxen

Date: 18:12:15 05/01/01

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On May 01, 2001 at 19:22:22, Paul wrote:

>On May 01, 2001 at 18:59:04, Paul wrote:
>
>>On May 01, 2001 at 17:55:59, Heiner Marxen wrote:
>>
>>>Here are two PV lines from Chest:
>>>
>>>Qbxd8+ Qxd8  Qhxd8+ Nxd8 Qxd8+  Qxd8  gxf8Q+ Rxf8  Qxf7+  Rxf7   h8=Q+  Nf8
>>>Qxf8+  Rxf8   Rxd8+  Ke7    Bg5+   Rf6   Bxf6+  Kf7   Rf8+   Kxf8  Nxe6+  Ke8
>>>Qe7#
>>>
>>>Qdxd8+ Qgxd8 Qhxd8+ Nxd8 Qxd8+  Qxd8  gxf8Q+ Rxf8  Qxf7+  Rxf7   h8=Q+  Nf8
>>>Qxf8+  Rxf8   Rxd8+  Ke7    Bg5+   Rf6   Bxf6+  Kf7   Rf8+   Kxf8  Nxe6+  Ke8
>>>Qe7#
>>>
>>>They are basically equal. Other black moves lead to shorter solutions, except:
>>>8... Kxd8   Nxe6+  Bxe6  Bg5+   Kc8   Qexb8+ Qxb8  Qaxb8+ Kd7 Qe7#
>>>                                Kd7   Nxb8+  Kc8   Nxc6+  Kd7 Qed6#
>>>                                                          Qb8 Qbb7#
>>>                                             Qxb8  Qe7+   Kc8 Qexb8#
>>>                                             Rxb8  Qe7+   Kc8 Qd8#
>>>                                Rf6   Qxf6+  Kd7   Qfe7+  Kc8 Qd8#
>>
>>Hi Heiner,
>>
>>This was a nice position wasn't it? This is the second time in about 2 weeks
>>we've had a mate in 13 that's really a mate in 13! :)
>>
>>Just one question though ... my line was this one:
>>
>>1. Qbxd8+ Qxd8 2. Qhxd8+ Nxd8 3. Qxd8+ Qxd8 4. gxf8=Q+ Rxf8 5. Qxf7+ Rxf7 6.
>>h8=Q+ Nf8 7. Qxf8+ Rxf8 8. Rxd8+ Kxd8 9. Nxe6+ Bxe6 10. Bg5+ Kd7 11. Qe7+ Kc8
>>12. Qexb8+ Qxb8 13. Qxb8#
>>
>>which is the first of your 2 lines, with the 8... Kxd8 deviation, but then at
>>move 11 another deviation: Qe7+, you don't mention that one? I have a bug?
>
>Never mind ... I see now that you only mention other black moves ... :)
>
>Groetjes,
>Paul

Exactly!

Often I leave out duals (alternate attacker moves), except at the top level.
Including duals at all levels can explode the solution tree sometimes.

Here is the complete solution tree with all duals after 10...Kd7:

 Nxb8+ Kc8  Nxc6+  Kd7  Qbd6#
                        Qe7#
                        Qed6#
                   Qb8  Qbb7#
       Qxb8 Qe7+   Kc8  Qaxb8#
                        Qexb8#
       Rxb8 Qe7+   Kc8  Qd8#
       Ke8  Qe7#
 Qe7+  Kc8  Qaxb8+ Qxb8 Qxb8#
            Qexb8+ Qxb8 Qxb8#

Regards,
Heiner



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