New ideas in fairy chess 2 - SAT

So finally the dust has settled and the definitions of SAT family fairy conditions are hopefully definitive. The old definition given on this page, is rebaptized as a "Sharp SAT", while name "SAT" was given to simpler and understandable fairy condition. My view that SAT is a very fairy condition with good perspective, was proven by successful thematical tourney as well as other recent very interesting compositions by various authors. Compliments to Ladislav Salai sr., who invented the condition!

Definicie a komentar - Definitions and comment

SAT: strana je v sachu, pokial jej kral ma tah podla ostatnych (ortodoxnych, resp. dalsich) pravidiel. (Logicky, strana na tahu je v mate, pokial je v sachu rem a tato strana nemoze tento sach zrusit.)

SAT: a side is checked if its king can move according to other (orthodox or other given fairy) rules. (Logically, a side to move is checkmated if it is checked and it cannot parry the check by own move.)

I would like to emphasize that this definition is as consistent as possible and it is simple enough to be coded into solving program. As far as I know, it can be solved by special version of Popeye (When it will be included in official release? It is a question...) and also by WinChloe that allows its combinations with the many-many other fairy elements thanks to well fore-thought algorithms. (Great, Christian!)

The award of first section of abovementioned thematical tourney showed many interesting direct problems: some long moremovers, but also modern twomovers and above all it turned out SAT is very suitable for selfmates. The unofficial match between Czechia and Slovakia, running now, has one of sections dedicated to SAT selfmates. We will see...

Ostry SAT: strana je v sachu pokial jej kral ma aspon jedno volne pole. (Logicky, strana na tahu je v mate, pokial je v sachu rem a tato strana nemoze tento sach zrusit.) Od chvile prveho napadnutia krala superovym kamenom sa za volne pole povazuje aj pole, na ktorom sa kral nachadza, ak nie je napadnute superom.

Sharp SAT: a side is checked if its king has at least one flight. (Logically, a side to move is checkmated if it is checked and it cannot parry the check by own move.) Beginning by the first attack of king by enemy unit, the square occupied by king is considered to be his flight when this square isn't attacked.

Sharp SAT seems to me to be too complicated... but well, it exists and if someone likes it, he can try composing.

(Old definitions that appeared here had some defects that was caused by me. Thanks to Olivier Ronat for pointing it!)
Ladislav Salai
378 "Umenie 64" 10 - 1999

White king is immobilized (why?), pa7 cannot move as well. The only hope of white is in closing long diagonal h1-a8, giving special SAT flight a8. You can see 8 tries with opposition of rooks:

1.Rf8? Rf7!, 1.Re8? Re7!, 1.Rd8? Rd7!, 1.Rc8? Rc7!, 1.Rh6? Rg6!, 1.Rh5? Rg5!, 1.Rh4? Rg4!, 1.Rh3? Rg3!

Goes only 1.Rb8! ~ 2.Rb7#

#2 (6+5)
Sharp SAT

Ladislav Salai
4693 Sachova Skladba 63 12/1998

There is no big choice for both sides in this demonstration:

1.b3?? is illegal (flight a2)
1.bxa3? stalemate!

Works only 1.b4! a2 2.Bh7#


#2 (3+4)

Ladislav Salai
4694 Sachova Skladba 63 12/1998

1.a5! (zz)
1...Kg4 (takes potential flight f5, allows...) 2.Ke4#!!
1...b6 (takes potential flight c5, allows...) 2.Kd4#!!
1...Sb4 (takes potential flight c2, allows...) 2.Sd4#
1...Sc1 (takes potential flight e2, allows...) 2.e4#
1...b5! (takes potential flight c4, allows...) 2.Rg4# and now not 2...fxg4 as it would give new Sharp SAT flight h4.

#2 (6+11)
Sharp SAT

Ladislav Salai
379v "Umenie 64" 10 - 1999

1.d3! th. 2.dxc4#,
1...c3 2.d4+ c4
3.d5+ c5
4.d6+ Sc6
5.d7 c2
6.d8B! th. 7.Bxb6#
6...Rb6~b (opens d8-a5), Ra6! (blocks a6, but covers potential white flight a2) 7.Ba5# (flight a6), Rxc2# (flight a4)

Very interesting excelsior and unexpected final mates.


#7 (3+7)

Ladislav Salai
380 "Umenie 64" 10 - 1999

Black can move only his pawns on 7th rank and white sees that two moves by any of them leads to mate. So he simply immobilizes the unmoved pawn on his second move.

Unfortunately, knight c5 is too agile, he not only guards b2, but can access a5 as well... Thus intentions:

1.a8B? (zz) 1...b6, c6 2.Bc6, Bxb7 bxa5#, cxb5#
but 1...b6! 2.Bc6 bxa5+! 3.Sxa5 (# by the way)

1.a8S? (zz) 1...b6, c6 2.Sxc7, Sb6 bxa5#, cxb5#
but 1...b6! 2.Sxc7 bxa5+! 3.Sxa5 (# by the way)

s#2 (5+5)
2 solutions

Ladislav Salai
4695 Sachova Skladba 63 12/1998

1.d2 g5 2.Bf5 Rg1#

1.Bxg4 b4 2.Be6 Sc1#

1.Bf2 c4 2.Bd4 Sd1#

Triple "unpin" and line openings. Note that in 3rd solutions Black cannot parry check by 3.Bg1 due to Sharp SAT flight h1.

h#2 (7+8)
Sharp SAT

Ladislav Salai
381 "Umenie 64" 10 - 1999

1.Rc6 Be6 2.Rxe6(Bf1) Bxd3#?? 3.Kd5+!

1.Sb2 Sxb7 2.Bxb7(Sb1) Sxc3#?? 3.Kd5+!

1.b6 a5 2.bxa5(pa2) axb3#?? 3.Kb5+!

A try to join two fairy conditions. I can't believe there is no cook. Can you find any?

Yes, Olivier Ronat found one:
1.Nb2 a5 2.Rg4/Rh4 Kb5#

And WinChloe found tons of cooks. Never mind, helpmate in SAT isn't so hopeless as it may seem. from this example... moreover Bojan Basic have shown that neither from intended solutions solves...

h#2 (5+10)
SAT, Circe

Comments to Juraj Lörinc.
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