No.807 (PAP)

Petko A. Petkov


Original Problems, Julia’s Fairies – 2015 (I): January – June

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No.807 by Petko A. Petkov – Paradoxical play of the bR in a rich thematic complex, created by combination of Disparate(Py) and Andernach conditions! Model mates in four phases.  Compare with author’s previously published problems (JF’s no. 429523, 566 were Disparate is combined with Anti-Andernach. (JV)


Disparate(Py): If one side makes a move with a piece of type “x” (black, white, neutral, half-neutral, etc., King included), the other side cannot answer immediately by moving a piece of the same type “x”. (For example: white Qc1, black Ka8,Qa7 – mate in 1 move. After 1.Qc8#, Black is mated because 1…Qb8? is illegal. The mate is possible also with the neutral nQc1 – after 1.nQc8#. Black cannot move the same neutral Queen.) Every Pawn’s promotion is a Pawn’s move, therefore after such promotion (into any possible piece) the other side cannot answer immediately with its Pawn. We can say that after the move of the figure of type “x” any enemy figure of type “x” falls under Half-moving paralysis. This paralysis disappears immediately on the next half-move, if the opponent plays with another piece of type “y”. (This way it is implemented in Popeye. Another implementation of Disparate you can find in WinChloe, but it is based on the different rules. )

Andernach Chess: A piece (excluding King) changes its color after any capturing move. Rooks on a1, h1, a8 and h8 can be used for castling, provided the usual other rules for that move are satisfied.

Nightrider(N): (1,2) Rider. Operates along straight lines with squares lying a Knight’s move away from each other.

Camel(CA): (1,3) Leaper.

No.807 Petko A. Petkov

original – 17.05.2015

Solutions: (click to show/hide)

White kb1 bc7 cab3b7 nf1h2 pc3d3 Black kc5 rb8

hs#2,5                                       (8+2)
b) Pd3→d5; c) Pd3→e4; d) Pd3→a4
Disparate (Py)
Camels: b3, b7
Nightriders: f1, h2

8 Responses to No.807 (PAP)

  1. Seetharamanseetharaman says:

    Beautiful problem! I like the andernach-disparate combination enabling nice zugzwang mates from the black king. IF white king had no flight square, I suppose capture of the white figures by any other black pawn/piece will also be mate. ?

  2. Kenneth Solja says:

    So do I understand this correctly?
    W3 in every solution is a check, but it needs BK to move to make a mate?

    • JuliaJulia says:

      W3 is not a check yet (otherwise it would be an illegal move!), because a black piece appeared by Andernach condition just after the white move is paralyzed by Disparate.
      Like, in a) 3.CAb7xa4=b: Camel goes from b7 to a4 and changes its color into black; this new black piece CAa4 is paralyzed by Disparate because of just made white move of CA, so there is no check! But the next capture by the bK has two reasons: 1) after move of K (actually, after any black move) Camel is not paralyzed anymore, so check will be possible; 2) but to have a mate, the white Camel must be captured, as otherwise with any move it can paralyze the bCA again, and avoid mate.
      Same in all twins. Beautifully!

  3. Kjell Widlert says:

    The play is really fairly simple, once you have the idea about how to connect the different components of the problem – but to have that idea required some very good thinking!
    No cookstoppers on the board.

  4. C. Poisson says:

    In 2002 or 2003, when I was fairy redactor for Phénix, Roméo Bédoni sent me an article about a new condition called Echecs Disparates. I immediately programmed the condition in WinChloe, exchange with him because some problems were unsound, and finally redact the article which appeared in 2004.
    Few years later, the Popeye team, programmed also a condition they name Disparate (I suppose after Mr. Petkov ask them to do it), but it is not the original Disparate, as Andernach is not Tibet.
    You can desagree with the way a condition is first defined and programmed, but if you modify it, you don’t keep it’s original name.
    Mr. Petkov has simply to tell how he wants to name his condition (for instance something like “Disparate type Petkov”, or “Disparate II”, or …) and the problem will be solved.

  5. Petko A.Petkovpetko petkov says:

    Thank you, Christian! I believe it would be really a very good idea just to implement one more version of Disparate, and to call it “Disparate PY”. It was developed with inventor’s agreement, and also used in Roméo Bédoni 80JT (the Award published in Phénix in 2010).

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