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No.762 |
Original Problems, Julia’s Fairies – 2015 (I): January – June →Previous ; →Next ; →List 2015(I) Please send your original fairy problems to: julia@juliasfairies.com |
No.762 by Geoff Foster – Inverted echo mates with opposite fairy conditions (Back-To-Back & Face-To-Face) in two twins! (JV)
Definition:
Back-To-Back: When pieces of opposite colors stand back-to-back with each other on the same file (white piece is on the top of black!), they exchange their roles. A pawn on the first rank cannot move. Any piece can make an en passant capture when it has got a role of Pawn by Back-To-Back.
Face-To-Face: When pieces of opposite colors stand face-to-face with each other on the same file (black piece is on the top of white!), they exchange their roles. A pawn on the first rank cannot move. Any piece can make an en passant capture when it has got a role of Pawn by Face-To-Face.
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No.762 Geoff Foster |
Solutions: (click to show/hide) |
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Black Ke3
Neutral Qf7 Sf8
h#2,5 (0+1+2) |
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Illustrates the fact that BTB is just like FTF, only upside down!
By the way, a wonderful mate where Black cannot save himself by moving away the NQ.
The beauty is that the nS is virtually pinned in both the phases and cannot move. If it moves the nQ gets its original power. The other important effect is that the bK cannot capture the unsupported checking piece due to self check — in (a) due to BTB effect and in (b) due to FTF effect. Wondeful!
nS is not pinned. b1/c2 in a) and e2/f3 in b) are guarded only by white power of nQ.
White uses in both mates only the Q-power of both neutrals for double Queen-checks.
And Black might use only the S-power of both Neutrals but has no legal move 🙂
Thank you Nikola, I didn’t notice it. Many times I get confused with neutral pieces.
I am also confused about that.
So I try to remember that in a neutral BTB pair, there are 2 white pieces which may move like the lower piece, or 2 black pieces moving like the upper piece.
It’s an opposite case in a FTF pair, but still it’s tricky.
Here are two original examples for the exercise:
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Pieces Neutral Kd7 Ph6 Pe4
Stipulation h=3.5; Condition BackToBack
1…nPh7 2.nKe6 nPh8=nQ 3.nQe5+ nKa6 4.nPd5 nQd4=
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Pieces Neutral Kd5 Rc4 Pc2
Stipulation h=3.5; Condition ChameleonChess+BackToBack
1…nRc3=nQ 2.nKc4+ nKf1 3.nPg2+ nPg4 4.nKg1 nQg3=nS=