|
No.542 |
Original Problems, Julia’s Fairies – 2014 (II): May – August →Previous ; →Next ; →List 2014(II) Please send your original fairy problems to: julia@juliasfairies.com |
No.542 by Chris Feather – Nice thematic S-mates, surprising B-promotion! (JV)
Definitions (from Fairings No.32):
Symmetry Anti-Circe: As Anti-Circe except that the rebirth square for the capturing unit is that which is symmetrical in Symmetry Circe.
Anti-Circe: After a capture the capturing piece (Ks included) must immediately be removed to its game array square (necessarily vacant, else the capture is illegal). R, B & S go to the square of the same colour as the capture; Ps stay on the file of capture; fairy pieces go to the promotion square of the file of capture. [The default Calvet type (not usually specified) allows captures on the rebirth square, the rarer Cheylan variant (always to be specified) excludes them. In practice many problems can be of either type.]
Symmetry Circe: As Circe except that the rebirth square for the captured unit is that which lies at an equal distance (in a straight line) beyond the midpoint of the board. Thus a capture on c4 produces a rebirth on f5, a capture on g1 produces a rebirth on b8, and so on. Strictly speaking there are of course other types of symmetry: this one is rotational.
Circe: Captured units (not Ks) reappear on their game-array squares, of the same colour in the case of pieces, on the file of capture in the case of pawns, and on the promotion square of the file of capture in the case of fairy pieces. If the rebirth square is occupied the capture is normal.
|
No.542 Chris Feather
England
original – 07.05.2014
 ser-h#10* (7+3)Symmetry Anti-Circe Solution: (click to show/hide)
|
The black bishop can’t get back to f7 in time (the bPe6 blocks the way), but by capturing the wPb3 it can get to g6 without losing a move, enabling the wS to mate on b3. A very witty way of changing the set mate!
The problem could be extended by having the wPg5 lower down the board. For example, with wPg5 on g2 it would be ser-h#14.
Since the black pawn has to move, it can get back to f7 only through promotion and and it can promote only on the ‘h’ file. The white king blocks the F- file ! So it has to capture. Once the point is seen, I think the solving is easy (though I did not attempt 🙂 )
The point is that the black pawn does not go back to f7!
The point is that Seetharaman pointed out that bP obviously can’t go back to f7. Playing along the f-file would be stopped at f3 and 2.fxe5(bPe5-d4) would have a dead-end at d3 or a pointless switchback to f6. 2.fxg5 obviously leads to promotion on h1. With 2 moves left, bS would be too slow and also bB can’t reach f7 because of bPe6.
This kind of oscillation between the left and right halves of the board makes the play in Symmetry-AntiCirce nicely dynamic.