Julia's Fairies

No.523 (PAP)

Petko A. Petkov 


Original Problems, Julia’s Fairies – 2014 (I): January – April

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red-roses2No.523 by Petko A. Petkov – Transformation of initial double battery in a complicated Disparate problem! Petko dedicates this problem to the memory of his father, Andon Petkov (1914-2014) marking the 100th anniversary of his birth and the 70th anniversary of his tragic death from the communist regime in 1944. (JV)


Disparate: 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. )

Anti-Andernach: A piece (excluding King) changes its color after any non-capturing move. After capture, the piece retains its color. Rooks on a1, h1, a8 and h8 can be used for castling, provided the usual other rules for that move are satisfied. After castling, Rooks do not change color, If White makes a non-capturing move with neutral or halfneutral piece, that piece becomes black and vice versa.

NAO(NA): Moves as Nightrider, but captures only by hopping over a hurdle to any square beyond.

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

Rook-Lion(RL): Moves along Rook lines over another unit of either color to any square beyond that unit. A capture may be made on arrival, but the hurdle is not affected.

No.523 Petko A. Petkov
In the memory of my father, Andon Petkov
523-hs#2,5-paphs#2,5          2 solutions            (5+7)
Nightriders: a3, a4, e7, e8
NAOs: b4, e3
Rook-Lion a8
Solutions: (click to show/hide)

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Kjell Widlert
Kjell Widlert
March 31, 2014 00:20

Every piece except Sc5 (which guards a flight-square in the mates) is involved in the thematic play! There are no cookstoppers – a result of choosing the right matrix (which Petkov is famously good at).

Among all the thematic changes, the most impressive detail to me is how the battery move in B2 is determined: B1 has given up the guard of b1 or b2, so B2 must compensate by blocking with an AntiAndernach-produced white Nightrider!

Nikola Predrag
Nikola Predrag
March 31, 2014 21:18

The content is impressive enough and at first look the construction is also impressive – single non-thematic bSb4 to guard b3, without cookstoppers.
One might think that it is not so incredible because the fairy conditions prevent the cooks. For instance, if Black could play 1…VAa8-a5 without changing Vao’s colour, the troubles with check-parrying by wNao’s would be avoided. But AntiAndernach prevents that.

Such impression could not be more far from the facts. The combined conditions can actually produce innumerable cooks with paralyzed wK.
That reveals that bSc5 is also a miraculous cookstopper!
Unbelievable realization

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