[Retros] Precisions about Checkless Chess tourney

[Andrew Buchanan]

Hi Alain,

The recursive definition could pose problems if you have an infinite
sequence of alternating checks. But in regular chess it is impossible.
However at first I was surprised that the WinChloe implementation is
recursive, because this opens the door to an infinite loop in fairy chess.
On reflection, maybe that's the only way to do it though.

In Hochberg's "Outrageous Chess Problems" I think there is a checkless
problem involving a couple of nightriders, but I can't remember the details.

Yes DIttman doesn't need to cover b7 & b8 in his composition. The position
would be mate anyway.

Good luck with your judging.

Cheers,
Andrew.

-----Original Message-----
From: retros-bounces at janko.at [mailto:retros-bounces at janko.at] On Behalf Of
Alain BROBECKER
Sent: 26 May 2012 16:41
To: retros at janko.at
Subject: [Retros] Precisions about Checkless Chess tourney

Some precisions about the Checkless Tourney:

* Andrew Buchanan points out there's a discussion about cross checks
  here: http://www.chessvariants.org/usualeq.dir/checklss.html
  
  For this competition i will take a programmer's point of view:
  "A check is mate, and hence legal, if the only move parrying
  the check is a non mating check" (this is recursive and that's
  how Checkless chess is implemented in WinChloé). 
  
  K5kr/8/5Q2/8/8/8/8/8
  White to play mates with Qf6-g7# since Kg8xg7 is check without mate.

* Henrik Juel points out a small mistake (check in forward play)
  in my redaction of Wolfgang Dittman's problem solution:
  "(Les blancs au trait gagneraient par n+1.Cf7+ Rh5 n+2.Cxg3#)"
  Change it to: "n+1.Cxg3 ~ n+2.Cf7#"
  
Happy composing
Alain

Alain Brobecker (abrobecker at yahoo.com) |_  _  _ |_
http://abrobecker.free.fr/             |_)(_|(_|| ) of  Arm's Tech

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