[Retros] SPGs enabled by A1.3

[andrew buchanan]

Thanks for sending the 2 DR PGs. I am very happy that
some of these positions exist, and in particular that
there are so few of them!

--- Francois Labelle <flab at EECS.Berkeley.EDU> wrote:

> After a complete analysis of my x=5 massacre data, I

> found a total of 10

> PGs enabled by Article 1.3:

> 

> 4 PGs depend on insufficient material

> 6 PGs depend on a forced stalemate

> 

> Here's one example of each type. For each example I

> give the diagram, and

> two diagrams one ply before to show the A1.3-legal

> move and the

> A1.3-illegal move.

> 

> 1)

>  _________________ _________________

> _________________

> |                 |                 |               

>  |

> | . . . k . b . . | . . . R k b . . | . . . . . b .

> . | a) SPG in 17.0

> | . . . . . . . . | . . . . . . . . | . . . k . . .

> . |

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

> . | one ply before:

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

> . | b) 1 solution

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

> . | c) 427 solutions

> | . . . . K . . . | . . . . K . . . | . . . . K . .

> . |

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

> . |

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

> . |

>

|_________________|_________________|_________________|

> 

> Solution:

> 1. d4 e5 2. Bf4 exd4 3. Bxc7 Qxc7 4. Qxd4 Qxh2 5.

> Qxg7 Qxg1 6. Qxg8 Rxg8 7.

> Rxh7 Rxg2 8. Rxf7 Rxf2 9. Rxd7 Rxe2+ 10. Kxe2 Qxf1+

> 11. Ke3 Qxb1 12. Rxb7

> Qxa2 13. Rxb8 Qxb2 14. Rxa7 Qxc2 15. Rxc8+ Qxc8 16.

> Rxa8 Qd8 17. Rxd8+

> Kxd8

> 

> Forbidden solutions (one of them):

> 1. d4 e5 2. Bf4 exd4 3. Bxc7 Qxc7 4. Qxd4 Qxh2 5.

> Qxa7 Qxg1 6. Qxb8 Qxf2+

> 7. Kxf2 Rxa2 8. Qxb7 Rxa1 9. Rxh7 Rxb1 10. Rxh8 Rxb2

> 11. Rxg8 Rxc2 12. Rxg7

> Bxb7 13. Rxf7 Bxg2 14. Rxd7 Bxf1 15. Kxf1 Rxe2 16.

> Kxe2 Kxd7 17. Ke3 Kd8

> 

> 2)

>  _________________ _________________

> _________________

> |                 |                 |               

>  |

> | . . . . k . . . | . . . . k . . . | . . . . k . .

> . | a) SPG in 15.5

> | Q . . . B . . . | r Q . . B . . . | Q . . . B . .

> . |

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

> . | one ply before:

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

> . | b) 1 solution

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

> . | c) 32 solutions

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

> . |

> | . . . . K . . . | . . . . K . . . | . . . . q . .

> . |

> | . . . . . R N . | . . . . . R N . | . . . . K R N

> . |

>

|_________________|_________________|_________________|

> 

> Solution:

> 1. d4 Nh6 2. Bxh6 d6 3. Bxg7 Be6 4. Bxf8 Bxa2 5.

> Bxe7 Bxb1 6. Rxa7 Bxc2 7.

> Qxc2 Rg8 8. Qxc7 Rxg2 9. Qxd6 Rxh2 10. Qxb8 Rxf2 11.

> Qxb7 Qxd4 12. Rxh7

> Qxb2 13. Rxf7 Rxf1+ 14. Rxf1 Qxe2+ 15. Kxe2 Rxa7 16.

> Qxa7

> 

> Forbidden solutions (one of them):

> 1. d4 Nh6 2. Bxh6 d6 3. Bxg7 Be6 4. Bxf8 Bxa2 5.

> Bxe7 Bxb1 6. Rxa7 Bxc2 7.

> Qxc2 Rxa7 8. Qxc7 Rg8 9. Qxd6 Rxg2 10. Qxb8 Rxh2 11.

> Qxb7 Rxf2 12. Qxa7

> Qxd4 13. Rxh7 Qxb2 14. Rxf7 Rxf1+ 15. Rxf1 Qxe2+ 16.

> Kxe2

> 

> 

> REPLIES

> 

> Michel Caillaud wrote:

> 

> > R143 is "humanly" very difficult, and I think it

> can't be solved except

> > investing enormous time (which I will not try).

> 

> Maybe it's still possible to have fun with massacre

> PGs by asking a friend

> to play half of the moves for you (or 1/3 or 2/3

> depending on taste). Then

> you get two manageable sub-PGs: reaching the

> intermediate position, and

> reaching the final position from the intermediate

> position.

> 

> > Well, we cannot be absolutely sure that there are

> not undiscovered bugs

> > in Popeye, Natch or Euclide (and indeed some were

> found in the past),

> > nevertheless problems tested by them are admitted

> "C+".

> 

> The difference is that my program's purpose isn't to

> test, but to compose

> problems. The code in these other programs is

> stabilized, while my code

> keeps changing depending on which kind of problem I

> want to compose.

> Running it is also more complicated.

> 

> To decide what to do, first we can look at the

> precedents. Were the

> Wilts/Geissler massacres published as C+?

> 

> Personally I think that the proper way to phrase it

> would be to list

> "computer" as a co-author, because in this case its

> contribution is so

> important. This would tell people that the problem

> is almost certainly

> correct, and help explain how someone could possibly

> come up with this

> stuff. But according to the precedents this isn't

> done.

> 

> > Until now, your programming has proved rather

> performing, what gives a

> > high level of confidence in your results.

> 

> Yes, I'd say that R143 is about 96% certain, and 98%

> if it survives a

> simple manual check for duals. People shouldn't

> waste time trying to find

> a cook.

> 

> Andrew Buchanan wrote:

> 

> > As far as the Holy Grail is concerned, the hope is

> still out there for

> > the next generation to explore x=6.

> 

> It might be possible to check x>=6 faster by

> constraining the search to

> promising king positions only. I hope I have time to

> try this over the

> summer.

> 

> 	Francois

> 

> 

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