Tries in fairy problems 1

This is the first special example file for the 23rd TT CCM C 3.3.2008.

It everything has evolved somewhat unexpectedly. The preselected theme for the tourney was very different. But finally I have have selected this one, inspired by one of spots in my blog in Slovak language. Tries are often difficult to overcome in the twomover round at solving competitions, but sometimes their underlying motivation is worth the second look. And what about the third look? And what about the fairy view?

So, I had the theme chosen - and almost immediately after the announcement publication I have received in my mailbox the set of examples composed by Uri Avner. That has given me an impulse to provide this first example file. It includes one of Uri's works, but also seven other, all of them united by the important role of black promotions.
Jean-Pierre Boyer
Comm Europe Echecs 1968

1.Kd7? th. 2.Qa6#
1...g1S!

1.Ke7? th. 2.Qa6#
1...g1B!

1.Shf7? th. 2.Qa6#
1...g1R!

1.Sdf7? th. 2.Qa6#
1...g1Q!

1.Kf8! th. 2.Qa6#
1...g1~ 2.Qxg1#

The plan of White is simple: unpin the queen (that cannot be captured) and mate from a6. However 4 out of 5 possible unpins (not counting Qxh5) allow Black to defend successfully by precise promotion at g1. Twice wK walks into selfcheck, twice wSs unblock rebirth squares. Black completes AUW.

Nice early example of Circe possibilities. There are others and we may revisit them in the near future.









#2 (7+4)
Circe
Petko A. Petkov
dedicated to A.H. Kniest
1st Prize Schach-Echo 1970

1.Qc2? th. 2.Qc7#
1...f1N!

1.Qe4? th. 2.Qe7#
1...h1N!

1.Qf5? th. 2.Qd7#
1...g1N!

1.Gg6! th. 2.Nxf7+ Sxf7 3.Se6#
1...f1G 2.Qc2! th. 3.Qc7#
1...g1G 2.Qf5! th. 3.Qd7#, 2...Sxf5 3.Nxf7#
1...h1G 2.Qe4! th. 3.Qe7#, 2...Sg8, Sf5 3.Nxf7#
1...fxg6 2.Qxg6! th. 3.Se6#, 2...Sf7 3.Nxf7#

3 tries by wQ are refuted by nightrider promotions of 3 pawns. White forces other promotions by those pawns, namely grasshopper promotions, pinning white nightrider. The error is then impossibility to promote to nightrider - that is known as a Holst promotion.









#3 (7+13)
1+0 nightrider, 1+2 grasshopper
Michel Caillaud
3rd Prize diagrammes 1980-81

1.b8G? th. 2.Gh1 gxh1Q#
1...Kd6! Gc7#

1.b8Q? th. 2.Gh1 gxh1Q#
1...Kf6! Qd8#

1.b8B? th. 2.Gh1 gxh1Q#
1...Kf8! Bd6#

1.b8S? th. 2.Gh1 gxh1Q#
1...Kd8! Sc6#

1.b8R! th. 2.Gh1 gxh1Q#

4 white promotions are refuted by utilization of the reflex condition. The last one, rook promotion does not allow Black to force white mate. Thus Black is forced to mate by queen promotion - that is so usual in reflexmates...









r#2 (9+4)
3+2 grasshopper
Johan Christoffel van Gool
dedicated to A. Davaine
2nd Comm Rex Multiplex 1982

1.Rb1? zz
1...d1wQ!

1.Bf5? zz
1...d1wS!

1.Bc4? zz
1...d1wR!

1.Ba6! zz
1...d1wQ 2.Qd7! ~ 3.Qh3#
1...d1wS 2.Rb1! Bd2 3.Sxe3#
1...d1wR 2.Rb5! Kxe2 3.Rb1#
1...d1wB 2.Bc8! ~ 3.Bh3#

White knows that Black will present him one further piece at d1. So he has to provide for all possibilities and avoid stalemating black. Rb1 pins Be1 in anticipation, Bf5 provides flight and that counts after the knight promotion and finally Bc4 does not allow Indian manoeuvre. Variability, less unity, nevertheless AUW in the solution.









#3 (7+7)
Volages
Yves Cheylan
2nd Comm Probleemblad 1984

1.Rxf6? th. 2.Qxe6#
1...b1Q!

1.Qe5? th. 2.Bxe6#
1...b1B!

1.Qa8? th. 2.Qe8,Bxe6#
1...b1R!

1.Qb7! th. 2.Bxe6#
1...b1R 2.d8Q#
1...b1B 2.d8S#

Tries focus on the mate threat by capture on e6. Single Queen mate is naturally refuted by paralysis possibility, single bishop mate is refuted by immediate paralysis. Double threat is refuted by rook promotions paralysing Rf1 and thus unpinning Qf6. In the solution White sets up the battery and something unusual follows: mixed AUW in two variations. The dual avoidance is motivated by need to paralyse black defender unpinned by paralysis of wB/wR.









#2 (8+8)
Madrasi Rex Inclusiv
Norman A. Macleod
Comm Mat 1984

1.Sd4+?
1...d1R!

1.Sfd6+?
1...d1R 2.Se4#
1...d1S!

1.Sxg7+?
1...d1R 2.Qh6#
1...d1Q!

1.Sh6+!
1...d1R 2.Sg4#
1...d1Q 2.Qc2#
1...d1S 2.Sb2#
1...d1B 2.Bc2#

Interesting strategy is based on the triple rook paralysis and play of white knight. After random move of wS (represented by 1.Sd4+) there are prepared mates to all promotions except rook one. Thus White has to provide the mate and does that in two further tries. But 1.Sd6+ closes line of wB and makes Sb2 mate impossible and 1.Sxg7+ unblocks g7 and thus makes Qc2 mates impossible. What remains? Naturally the solution with the 3rd mate after 1...d1R!









#2 (12+8)
Madrasi
Petko A. Petkov
Phénix 1988 (v)

1.c8G? th. 2.Bc4#
1...c1CA!

1.c8CA? th. 2.Zf7#
1...c1N!

1.c8N? th. 2.Nf3#
1...c1Z!

1.c8Z? th. 2.Be3#
1...c1G!

1.c8Q! th. 2.Qxd7#
1...CAe4 2.Nf3#
1...Sc5 2.Bc4#
1...Gxc8 2.Zf1#
1...d6 2.Be3#
1...d5 2.Zf7#

The emphasis of tries is not put on the motivation of refutations as this is simple guarding of mates. Rather the idea is in the cyclic relationship between promotees in tries and refutations. Reappearance of all threat mates from tries in solution is welcome addition.









#2 (11+8)
2+1 grasshopper, 0+1 camel
1+0 nightrider, 1+1 zebra
Uri Avner
4th Prize 11th TT diagrammes 1993

1.Sce3+?
1...Qxb2!

1.Sb4+?
1...Sxb2!

1.Scd4+?
1...Bxb2!

1.Sxh4(Sg1)! th. 2.Sxh3(Sb1)#
1...hxg1Q(Qd8) 2.Se3#
1...hxg1S(Sb8) 2.Sb4#
1...hxg1B(Bf8) 2.Sd4#

Finally, Uri's problem. Three immediate checks from Anticirce battery P-S-K are refuted using the Anticirce typical unpinning by closing the line of potential check. Where are promotions? In the variations of solution! The defences offer Black trio of new promoted pieces Q, S and B, but their plaing on Circe squares means refutations of tries are no longer possible, one per variation.

By the way, this problem was placed in Album FIDE for years 1992-1994.









#2 (10+12)
Anticirce

Comments to Juraj Lörinc.
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