# [Retros] Series proof games leading to a checkmate in one move.

**Francois Labelle**
flab at wismuth.com

*Thu Nov 4 00:36:51 EDT 2010*

Hi Nicolas,

Nice challenge... for a computer!

I searched all such problems for N <= 12, and for N <= 9 + rank(wk),

where rank(wk) is the rank of the white king in the final position. I

found the following improvements (I also list ties if they're different

enough):

Pa7, 1 fewer capture

1.e3 5.Kb5 6.c4 7.Qa4 8.b3 10.Bxe7 12.Ba5 a6#

Pe7, 1 fewer move (2 different solutions)

1.c4 3.Qxa7 4.Qe3 5.d4 9.Kd5 10.Qe4 12.Be5 e6#

1.g4 4.Bxh7 6.Ba6 7.d3 11.Kg5 12.Bf4 e6#

Pg7, no improvement but different

1.c3 3.Qg4 4.d4 5.Bg5 6.f4 10.Kh5 11.h4 g6#

Ra8, no improvement but different

3.Nb5 4.d4 7.Kb4 8.c3 10.Qxa7 11.Qxb7 12.Qa6 13.Ka5 14.b4 Rxa6#

Because I did an exhaustive search up to N = 12, all the records with N

<= 12 are optimal. In addition, the record for Pd7 must be optimal

because it has 13 moves and no captures.

OTHER NEWS

I realize I haven't posted here in a while! I got some new computer

results in the last 3 years. I know all the proof games in 5.0 moves,

all the checkmate proof games in 6.0 moves, and all the one-sided proof

games in 11 moves. I haven't data-mined any of it yet, except for this

problem

rn1qkbnr/ppp2ppp/8/3p4/8/1b1P4/PP2PPPP/RNBQKBNR PG in 5.0 moves, 3

solutions

which is probably the best 3-solution PG of that length, and was used in

the Messigny 2008 retro solving contest.

Also Berkeley just closed my e-mail and web accounts, so I'm moving my

chess page from

http://www.cs.berkeley.edu/~flab/chess/chess.html to my own domain at

http://wismuth.com/chess/chess.html

My new e-mail address is the one I'm using for this message.

Francois

On Fri, 2010-10-22 at 12:37 +0200, Nicolas Dupont wrote:

>* Dear retro fans,
*

>*
*

>* The following series (exact) proof game has been discovered some years
*

>* ago, by various members of the french website France-Echecs :
*

>*
*

>* 1.c3 2.Qa4 7.Ka5 8.b4
*

>*
*

>* It leads to a checkmate in one move by the black side, namely c6#, and is
*

>* probably the shortest series proof game permitting such a #1.
*

>*
*

>* You can regard this as a kind of helpmate series problem, beginning with
*

>* the initial game array (and with reverse colors, i.e. we prefer white to
*

>* begin than black, this is more natural in that setting).
*

>*
*

>* Here the last move is with the c-pawn, and N, the number of white moves,
*

>* is 8. Andrew Buchanan and I proposed to extend this result, by asking :
*

>*
*

>* For each of the remaining black 15 pieces, which is the minimum value of N
*

>* achievable ?
*

>*
*

>* The massed brains of France-Echecs have achieved the following records
*

>* (thanks to Popeye, each of them is C+). Will you be able to beat some of
*

>* them ? Note that the above question makes also sense for black's 0-0 and
*

>* 0-0-0, but we were unbable to find a solution in those tricky cases. Note
*

>* also that the black move has not to be unique, neither giving check, i.e.
*

>* we only need that a move by the selected black piece leads to a checkmate.
*

>*
*

>* Our purpose is to write an article incorporating the best results, with
*

>* the scope that they are really the length records. That is why we need
*

>* your help... If you are able to show a game with same number of
*

>* moves, but fewer captures, this is considered as an improvement.
*

>*
*

>* Thanks and all the best,
*

>*
*

>* Nicolas.
*

>*
*

>* Pa7 (Nicolas Dupont) 12 moves
*

>* 1.e3 2.Bb5 3.d3 7.Ka5 8.b4 10.Bxg7 12.Bb6 and then axb6#
*

>*
*

>* Pb7 (Arthur Dupont) 11 moves
*

>* 1.a4 3.Rh3 4.e3 5.Bb5 6.d3 10.Ka5 11.b4 and then b6#
*

>*
*

>* Pc7 (France-Echecs) 8 moves
*

>* 1.c3 2.Qa4 7.Ka5 8.b4 and then c6#
*

>*
*

>* Pd7 (Jean-Christian Galli) 13 moves
*

>* 2.a5 4.Re4 5.d4 9.Ke5 10.Bf4 11.e3 13.Bd5 and then d6#
*

>*
*

>* Pe7 (Jean-Christian Galli) 13 moves
*

>* 2.h5 4.Rd4 5.e4 9.Kd5 10.Bc4 11.d3 13.Be5 and then e6#
*

>*
*

>* Pf7 (Jacques Dupin) 12 moves
*

>* 1.h4 4.Rxd7 6.Re4 7.d4 11.Ke5 12.Bf4 and then f6#
*

>*
*

>* Pg7 (Arthur Dupont) 11 moves
*

>* 1.h4 3.Ra3 4.d3 5.Bg5 6.e3 10.Kh5 11.Qg4 and then g6#
*

>*
*

>* Ph7 (Nicolas Dupont) 12 moves
*

>* 1.d3 2.Bg5 3.e3 7.Kh5 8.g4 10.Bxb7 12.Bg6 and then hxg6#
*

>*
*

>* Ra8 (Andrew Buchanan) 14 moves
*

>* 4.axb7 5.Rxa7 7.Rh3 8.d3 10.Nf3 11.Bd2 12.Qa1 14.Kc1 and then Rxa1#
*

>*
*

>* Nb8 (Jacques Dupin) 12 moves
*

>* 1.h4 4.Rxd7 6.Re4 7.d4 11.Ke5 12.Bf4 and then Nc6#
*

>*
*

>* Bc8 (Jean-Christian Galli) 14 moves
*

>* 4.dxe7 5.exf8=B 7.Bfg3 8.Bcf4 9.e3 13.Kh3 14.Qxd7+ and then Fxd7#
*

>*
*

>* Qd8 (Andrew Buchanan) 10 moves
*

>* 4.fxe7 5.exf8=N 6.Nxd7 9.Nh6 10.g4 and then Qh4#
*

>*
*

>* Ke8 (Nicolas Dupont & Jean-Christian Galli) 28 moves
*

>* 1.a4 4.Rxh7 6.Re3 11.hxg8=N 13.Nxf7 14.Nxh8 16.Nxf8 19.Nfb5 20.d4
*

>* 27.Kh8 28.Rh7 and then Kf7#
*

>*
*

>* Bf8 (Nicolas Dupont & Andrew Buchanan) 15 moves
*

>* 1.a4 4.Rxd7 5.d3 6.Bf4 7.e3 9.Bh5 10.f3 13.Kh4 14.Bg3 15.Rxe7+ and then
*

>* Bxe7#
*

>*
*

>* Ng8 (Nicolas Dupont) 11 moves
*

>* 1.h4 4.Rg5 5.g3 6.Bh3 11.Kh5 and then Nf6#
*

>*
*

>* Rh8 (Andrew Buchanan) 12 moves
*

>* 4.hxg7 5.Rxh7 7.Ra3 8.e3 10.Nc3 11.Be2 12.Kf1 and then Rh1#
*

>*
*

>*
*

>*
*

>*
*

>* _______________________________________________
*

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*

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*

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