[Retros] No occupied white square

Francois Labelle flab at wismuth.com
Mon Dec 9 17:19:58 EST 2013

On 12/06/2013 12:28 PM, Noam Elkies wrote:

> Heinonen's problem was still the first of its kind

Well technically there were earlier realizations with massacre proof
games like
http://pdb.dieschwalbe.de/search.jsp?expression=PROBID=%27P0004246%27 .

> And you've already published some

> of your earlier computer discoveries in problem magazines, so why not these?

Maybe because that one wasn't particularly hard to program and to
compute, but if the result is interesting then I guess that's what
counts. I'll try to get them published.

Some extra facts:
- 10.0 is also the minimum length for a non-unique proof game (for both
white squares and black squares). This was Eric's original question.
- There are two unique proof games of length 10.0 with men on white
squares, but the solutions are almost the same (one has 1 more capture,
leaving 20 men standing).
- There's only one unique proof game of length 10.0 with men on black

So my two PGs are essentially unique.

> P.S. Is it feasible to compute how many such proof games there are in

> 10.5 or even 11.0 and beyond? It would be interesting to see what

> the range of possibilities is (and how much choice Heinonen had for

> his 11.0-mover).

The search in 10.5 moves just completed. There are 177 and 98 unique
proof games with men on white squares and black squares (respectively).
I extrapolate that 11.0 moves will take 2 months, so I'm not sure if
I'll do it.

On 12/07/2013 02:23 AM, "Bernd Gräfrath" wrote:


> I would also like to see your two problems published in a magazine,

> preferably side by side; and the pioneer problem by Unto could be

> mentioned in the comments.

By the way Olli informed me privately that Unto found a 10.5-mover
(before he was informed of my 10.0 movers). If I publish my problems I
could also mention any of Unto's problems (if Unto is interested).

> By the way: I think that computer-helped discoveries can also qualify

> for awards, and even for the FIDE-Album.

I think so too, although such problems might be harder to judge. A
problem that is impressive to a human composer might have been easy to
generate by computer. Is this unfair? On the other hand, treating all
computer-helped discoveries as "easy to generate" would be wrong,
because they might not be.

> (I hope that you have sent your recent 2-King-PG to the FIDE-Album?)

Yes I did send it. Fingers crossed!


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