Allan Bell allanb at gofree.indigo.ie
Wed Oct 4 11:10:50 EDT 2006

Yes, that does the trick - a2 is the right place for the BB. The bishop on a2 would capture the knight without the check from the rook, and it would interpose on b3 without the check from the knight. That is what I meant by both checks being necessary. (and the only mating move by the WS is to return to b1 since b5 is occupied)

Regards,

Allan.
----- Original Message -----
From: Paul R
To: retros at janko.at
Sent: Wednesday, October 04, 2006 9:19 AM
Subject: [Norton AntiSpam] [Retros] RE : Retros Digest, Vol 22, Issue 1

It achieves the task, but the double check is not required to give mate
(sufficient, but not necessary). Is there a short game where the final
double-check on the home square is the only move to deliver mate?

Regards,

Allan.

Yes, for ex:
Popeye WINDOWS-32Bit-Version 3.81 (4 MB)
1.a2-a4 d7-d6 2.Ra1-a3 Ke8-d7 3.Ra3-d3 Kd7-c6 4.Sb1-c3 Kc6-c5 5.b2-b4 + Kc5*b4 6.Bc1-a3 + Kb4*a3 7.Qd1-b1 Bc8-e6 8.Qb1-b5 Be6-a2 9.Sc3-b1 dia
Ragards,

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than "Re: Contents of Retros digest..."

Today's Topics:

2. Current best solutions to my task :
(Nicolas.Dupont at math.univ-lille1.fr)
3. Re: Current best solutions to my task : (Christoph Fieberg)
4. Re: Current best solutions to my task : (Joost de Heer)
5. Re: Current best solutions to my task :
(Nicolas.Dupont at math.univ-lille1.fr)
6. Captureless exact proof game showing Nb8->b1 and Ng8->g1.
(Nicolas.Dupont at math.univ-lille1.fr)
7. Re: Task - double check mate (Allan Bell)
8. Task - double check mate (raosorio at fibertel.com.ar)
9. Re: Task - double check mate (Allan Bell)

----------------------------------------------------------------------

Message: 1
Date: Wed, 27 Sep 2006 20:38:38 -0400 (EDT)
From: Noam Elkies
To: retros at janko.at
Message-ID: <200609280038.k8S0ccN26596 at abel.math.harvard.edu>

I wrote:

" > Rook without capture : 9 moves (Itamar Faybish)

" This at least is not optimal:

" 1 f3 h5 2 Kf2 h4 3 Qe1 h3 4 Kg3 Nf6 5 Qf2 Rg8 6 Kh4 Se4 7 g3 f5 8 Qg2 Rh8#

" (C+ Popeye very quickly), and one can probably go below 8.0
" with some more effort.

Indeed here's one in 7.5 (C+ Popeye in <1 sec.):

1 h4 e6 2 h5 Qh4 3 h6 Qe4 4 f4 f6 5 Nf3 Kf7 6 Rg1 Kg6 7 Ne5+ Kh5 8 Rh1#

--Noam D. Elkies

------------------------------

Message: 2
Date: Thu, 28 Sep 2006 04:27:32 +0200 (CEST)
From: Nicolas.Dupont at math.univ-lille1.fr
Subject: [Retros] Current best solutions to my task :
To: "The Retrograde Analysis Mailing List"
Message-ID:
<1602.81.20.211.142.1159410452.squirrel at mathwebmail.univ-lille1.fr>
Content-Type: text/plain;charset=utf-8

King without capture : 5.5 moves (Noam Elkies)
1.d4 f6 2.Qd3 Kf7 3.Qh3 Kg6 4.Kd2 Kg5 5.Nc3 Kf4 6.Ke1#
King with capture : not least

Knight without capture : 6 moves (Itamar Faybish)
1.e3 e6 2.Ke2 Bd6 3.Kf3 Qf6+ 4.Kg4 Ne7 5.Kh5 g6+ 6.Kh6 Ng8#
Knight with capture : not least

Queen without capture : 6 moves (Joachim Iglesias)
1.d3 d6 2.Kd2 Bd7 3.Kc3 Qc8 4.Kb4 c5+ 5.Ka5 Bc6 6.b4 Qd8#
Queen with capture : not least

Bishop without capture : 6.5 moves (Itamar Faybish)
1.e4 e5 2.Ne2 Ke7 3.Nec3 Kf6 4.Be2 Kg5 5.d3+ Kh4 6.g3+ Kh3 7.Bf1#
Bishop with capture : not least

Rook without capture : 7.5 moves (Noam Elkies)
1.h4 e6 2.h5 Qh4 3.h6 Qe4 4.f4 f6 5.Nf3 Kf7 6.Rg1 Kg6 7. Ne5+ Kh5 8.Rh1#
Rook with capture : 6 moves (Joachim Iglesias)
1.e3 e6 2.Ke2 Ne7 3.Kf3 Rg8 4.Kg4 h5+ 5.Kxh5 Nec6 6.Qg4 Rh8#

------------------------------

Message: 3
Date: Thu, 28 Sep 2006 22:55:21 +0200
From: Christoph Fieberg
Subject: Re: [Retros] Current best solutions to my task :
To: The Retrograde Analysis Mailing List
Message-ID: <6.2.3.4.2.20060928225227.02b138e8 at pop.1und1.com>
Content-Type: text/plain; charset=us-ascii; format=flowed;
x-avg-checked=avg-ok-F9837E8

Hello Nicolas,

Bishop with capture:
1.e4 e6 2.Bb5 Ke7 3.Bxd7 Kf6 4.Bb5 Kg5 5.Nh3+ Kh4 6.g3+ Kxh3 7.Bf1# ?

Best regards,
Christoph

At 04:27 28.09.2006, you wrote:

>King without capture : 5.5 moves (Noam Elkies)
>1.d4 f6 2.Qd3 Kf7 3.Qh3 Kg6 4.Kd2 Kg5 5.Nc3 Kf4 6.Ke1#
>King with capture : not least
>
>Knight without capture : 6 moves (Itamar Faybish)
>1.e3 e6 2.Ke2 Bd6 3.Kf3 Qf6+ 4.Kg4 Ne7 5.Kh5 g6+ 6.Kh6 Ng8#
>Knight with capture : not least
>
>Queen without capture : 6 moves (Joachim Iglesias)
>1.d3 d6 2.Kd2 Bd7 3.Kc3 Qc8 4.Kb4 c5+ 5.Ka5 Bc6 6.b4 Qd8#
>Queen with capture : not least
>
>Bishop without capture : 6.5 moves (Itamar Faybish)
>1.e4 e5 2.Ne2 Ke7 3.Nec3 Kf6 4.Be2 Kg5 5.d3+ Kh4 6.g3+ Kh3 7.Bf1#
>Bishop with capture : not least
>
>Rook without capture : 7.5 moves (Noam Elkies)
>1.h4 e6 2.h5 Qh4 3.h6 Qe4 4.f4 f6 5.Nf3 Kf7 6.Rg1 Kg6 7. Ne5+ Kh5 8.Rh1#
>Rook with capture : 6 moves (Joachim Iglesias)
>1.e3 e6 2.Ke2 Ne7 3.Kf3 Rg8 4.Kg4 h5+ 5.Kxh5 Nec6 6.Qg4 Rh8#
>_______________________________________________
>Retros mailing list
>Retros at janko.at
>http://www.pairlist.net/mailman/listinfo/retros

------------------------------

Message: 4
Date: Thu, 28 Sep 2006 23:27:51 +0200
From: Joost de Heer
Subject: Re: [Retros] Current best solutions to my task :
To: The Retrograde Analysis Mailing List
Message-ID: <451C3E57.5050502 at sanguis.xs4all.nl>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Christoph Fieberg schreef:
> Hello Nicolas,
>
> Bishop with capture:
> 1.e4 e6 2.Bb5 Ke7 3.Bxd7 Kf6 4.Bb5 Kg5 5.Nh3+ Kh4 6.g3+ Kxh3 7.Bf1# ?

The record for capture-games should be shorter than the record for
captureless games.

------------------------------

Message: 5
Date: Thu, 28 Sep 2006 23:47:38 +0200 (CEST)
From: Nicolas.Dupont at math.univ-lille1.fr
Subject: Re: [Retros] Current best solutions to my task :
To: "The Retrograde Analysis Mailing List"
Message-ID:
<2415.81.20.213.151.1159480058.squirrel at mathwebmail.univ-lille1.fr>
Content-Type: text/plain;charset=utf-8

>From Joost :

> The record for capture-games should be shorter than the record for
> captureless games.

Yes. A little confusion comes from my wrong term "not least", which must
be change by "no less".

It's rather strange that, except for the rook case, minima can be
captureless.

------------------------------

Message: 6
Date: Sun, 1 Oct 2006 21:43:55 +0200 (CEST)
From: Nicolas.Dupont at math.univ-lille1.fr
Subject: [Retros] Captureless exact proof game showing Nb8->b1 and
Ng8->g1.
To: "The Retrograde Analysis Mailing List"
Message-ID:
<1241.81.20.209.58.1159731835.squirrel at mathwebmail.univ-lille1.fr>
Content-Type: text/plain;charset=utf-8

I found the following :

1.Cg1-h3 Pe7-e5 2.Ch3-f4 Ff8-a3 3.Pb2-b4 Cg8-f6 4.Fc1-b2 Cf6-e4 5.Fb2-d4
Fa3-c1 6.Cb1-a3 Ce4-g5 7.Ta1-b1 Cg5-h3 8.Tb1-b3 Ch3-g1 9.Tb3-h3 Cb8-c6
10.Pc2-c3 Cc6-a5 11.Dd1-a4 Ca5-c4 12.Da4-c6 Pa7-a5 13.Ca3-b5 Cc4-a3
14.Fd4-e3 Ca3-b1

Is it possible to construct it in fewer moves ?

Nicolas Dupont.

------------------------------

Message: 7
Date: Sun, 1 Oct 2006 21:08:13 +0100
From: "Allan Bell"
Subject: Re: [Retros] Task - double check mate
To: "The Retrograde Analysis Mailing List" ,

Message-ID: <001301c6e595\$86482280\$29cd7dc2 at allanb>
Content-Type: text/plain; charset="iso-8859-1"

----- Original Message -----
From: "Noam Elkies"
To: ;
Sent: Sunday, September 24, 2006 2:49 AM

> > In the web-site "France-Echecs", I proposed the following problem :
> > Construct the shortest possible exact proof game ending by a check-mate
> > given by a piece returning at home.
>
>
> > Here are our records, the 2 sections depending on whether or not
> > some piece is captured during the game :
>
> There could also be separate sections for discovered, direct
> and double check (though of course not all pieces can do
> all of them).

As suggested by Noam, here is a double check-mate (with captures) given by
a piece returning to its home square. Both checks are required.

1.Pa2-a4 Pe7-e5 2.Ra1-a3 Ke8-e7 3.Ra3-e3 Ke7-d6
4.Sb1-c3 Kd6-c5 5.Pb2-b4 Kc5xb4 6.Bc1-a3 Kb4xa3
7.Qd1-b1 Pb7-b5 8.Qb1xb5 Bf8-b4 9.Ke1-d1 Pd7-d6
10.Kd1-c1 Bc8-f5 11.Kc1-b1 Bf5xc2 12.Kb1-a1 Pf7-f5
13.Sc3-b1

C+ Natch

But there must be a shorter setting.

Allan Bell

>
> > Knight with capture : not least [...]
>
> What does "not least" mean?
>
> > Rook without capture : 9 moves (Itamar Faybish)
>
> This at least is not optimal:
>
> 1 f3 h5 2 Kf2 h4 3 Qe1 h3 4 Kg3 Nf6 5 Qf2 Rg8 6 Kh4 Se4 7 g3 f5 8 Qg2 Rh8#
>
> (C+ Popeye very quickly), and one can probably go below 8.0
> with some more effort.
>
> --Noam D. Elkies
> _______________________________________________
> Retros mailing list
> Retros at janko.at
> http://www.pairlist.net/mailman/listinfo/retros
>
>

------------------------------

Message: 8
Date: Mon, 02 Oct 2006 08:28:08 -0300
From:
Subject: [Retros] Task - double check mate
To: unlisted-recipients:; (no To-header on input)
Content-Type: text/plain; charset=us-ascii

Allan Bell wrote,

As suggested by Noam, here is a double check-mate (with captures) given by
a piece returning to its home square. Both checks are required.

1.Pa2-a4 Pe7-e5 2.Ra1-a3 Ke8-e7 3.Ra3-e3 Ke7-d6
4.Sb1-c3 Kd6-c5 5.Pb2-b4 Kc5xb4 6.Bc1-a3 Kb4xa3
7.Qd1-b1 Pb7-b5 8.Qb1xb5 Bf8-b4 9.Ke1-d1 Pd7-d6
10.Kd1-c1 Bc8-f5 11.Kc1-b1 Bf5xc2 12.Kb1-a1 Pf7-f5
13.Sc3-b1

But there must be a shorter setting.

Here is one without captures,

1.Pe2-e3 Pd7-d6 2.Ke1-e2 Bc8-h3 3.Ke2-f3 Pe7-e6
4.Kf3-f4 Sg8-e7 5.Kf4-g5 Pg7-g6 6.Kg5-f6 Se7-g8
natch 0.22 s

Regards,

------------------------------

Message: 9
Date: Tue, 3 Oct 2006 15:52:01 +0100
From: "Allan Bell"
Subject: Re: [Retros] Task - double check mate
To: "The Retrograde Analysis Mailing List" ,

Content-Type: text/plain; charset="iso-8859-1"

Yes. It's a pity that all other knight moves are mate as well, including
the other double-check mate 6.... Se7-d5.

It achieves the task, but the double check is not required to give mate
(sufficient, but not necessary). Is there a short game where the final
double-check on the home square is the only move to deliver mate?

Regards,

Allan.

----- Original Message -----
From:
To: ;
Sent: Monday, October 02, 2006 12:28 PM
Subject: [Retros] Task - double check mate

>
> Allan Bell wrote,
>
> As suggested by Noam, here is a double check-mate (with captures) given by
> a piece returning to its home square. Both checks are required.
>
> 1.Pa2-a4 Pe7-e5 2.Ra1-a3 Ke8-e7 3.Ra3-e3 Ke7-d6
> 4.Sb1-c3 Kd6-c5 5.Pb2-b4 Kc5xb4 6.Bc1-a3 Kb4xa3
> 7.Qd1-b1 Pb7-b5 8.Qb1xb5 Bf8-b4 9.Ke1-d1 Pd7-d6
> 10.Kd1-c1 Bc8-f5 11.Kc1-b1 Bf5xc2 12.Kb1-a1 Pf7-f5
> 13.Sc3-b1
>
> But there must be a shorter setting.
>
> Here is one without captures,
>
> 1.Pe2-e3 Pd7-d6 2.Ke1-e2 Bc8-h3 3.Ke2-f3 Pe7-e6
> 4.Kf3-f4 Sg8-e7 5.Kf4-g5 Pg7-g6 6.Kg5-f6 Se7-g8
> natch 0.22 s
>
> Regards,
>
> _______________________________________________
> Retros mailing list
> Retros at janko.at
> http://www.pairlist.net/mailman/listinfo/retros
>
>

------------------------------

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