‘White to play and checkmate in two moves’. You wouldn't miss such a short combination in a
game. Surely chess problems stipulating ‘White to play and mate in 2’ (or, more usually, #2)
are not that simple? No, they are not! Look at just some of the basic types of ‘twomovers’,
and decide for yourself. Some amazing ideas that might never have occurred to you in
overtheboard play will be revealed:
(1) Threat Problems
The obvious way to overwhelm Black is to threaten an irrefutable checkmate. But is it an
obvious keymove, the white King's advance into a barrage of checks?
G Guidelli
2nd Prize, L'Eco degli Scacchi, 19161917
Mate in 2

1.Kf7! (threat 2.Qb8#)
1...Ke5 2.Sc4;
1...e5+ 2.S7d5;
1...Be5+ 2.S7f5;
1...Bxe7+ 2.Bxf4;
1...B else+ 2.S3f5.

(2) Waiting Problems
Sometimes, examination of the ‘White to play and mate in 2’ position reveals that every
Black move (or almost every black move) is set with a mating reply – Zugzwang. Is
there a White first move that provides for everything and waits for Black to commit
himself? Solvers found the keymove in David Shire's problem tricky to find:
D. J. Shire
The Problemist Supplement, 1997
Mate in 2

1.Kh2! (Waiting)
1...Rd2+ 2.Sxd2;
1...Rxf3 2.Qe4;
1...Rd4 2.Se5;
1...Re3 2.Sd2;
1...R else 2.Qxc3;
1...Sxa4 2.Qxa4;
1...S else 2.Qxa2;
1...B any 2.Q(x)b3.
Not, for example, 1.Kg3/h3? Re3!

(3) Mutates
Supposing there was no ‘simple’ waiting move to preserve the mates provided (set) for all
Black's moves, as in David Shire's problem? Before the keymove is made in Spiric's
problem, the solver sees the set mates following the black moves 1...Kd5, 1...d5 and
1...B any. But there is no waiting move that preserves this state of affairs. Imagine the
wonder of (eventually) finding the key move 1.Qh6! Waiting. Now, we see some changed mates
following the black moves. The white Queen has craftily ambushed herself behind 3 men!
I. Spiric
The Problemist, 2002
Mate in 2

Set play:  Actual play: 1.Qh6! Waiting. 
1...Kd5 2.Qf3;  1...Kd5 2.Qh1; 
1...d5 2.Qxc7;  1...d5 2.Se5; 
1...B any 2.S(x)e7.  1...B any 2.S(x)e7. 

(4) Threat Problems with Set Play + Changed Play
Most compositions which change set mates are not in the Waiting (or Block) form of
Spiric's Mutate, but in the freer form of a keymove making a second move
threat. Prominent black moves set with mates in Swane's problem catch the solver's
attention, and make him reluctant to abandon them in his search for a solution. It's more
than likely that the solver will see first the set play. How long would it take him
to find the keymove 1.Se4! (threat 2.Qxb3#)? from which three changed mates result!
J. A. W. Swane
1st Prize, Magasinet, 1952
Mate in 2

 Actual play: 
Set play:  1.Se4! (threat 2.Qxb3#) 
1...Rxd3 2.Qa4;  1...Rxd3 2.Qxc5; 
1...S2xd3 2.Re4;  1...S2xd3 2.Sd6; 
1...S4xd3 2.Bd5.  1...S4xd3 2.Sd2; 
 1...Kxd3 2.Qxb3. 

(5) Try Play Problems
Chess composition – for long with the postkey play and setplay/postkey combinations of
the first four problems – gained another dimension with the studied introduction by
composers of try play. Which of the likely moves 1.Kxd5 or 1.Kxd7 should White play in the
following problem? Two parallel lines of play are woven into one problem.
B. P. Barnes
The Problemist, 2002
Mate in 2

Try play: 1.Kxd5? Waiting  Actual play: 1.Kxd7! Waiting 
1...b6/b5 2.Rxd7;  1...b6/b5 2.Kd6; 
1...c3 2.Kd6;  1...c3 2.Bxd5; 
1...d6 2.Rxb7;  1...d4 2.Bxc4; 
1...Sxf6+ 2.Qxf6;  1..Sxf6+ 2.Qxf6; 
1...S else 2.R(x)f8;  1...S else 2.R(x)f8; 
1...gxh5 2.Qg7;  1...gxh5 2.Qg5; 
but there is no mate for 1...e4!  1...e4 2.Qxd5;. 

(6) Set Play + Try Play + Changed Play Problems
Ever more is packed into the ‘modern’ twomove chess problem. It is unlikely that the
solver will miss the set mates in Slesarenko's problem. You might think you have solved the
problem and changed the mates after the black King flights with 1.Qa1? but 1...b5
(freeing c6) refutes the try. The key is 1.Qh7! (2.Qe4#) with changed mates and some
lovely byplay. To give you a taste of chess problem jargon, this is a 3 (phases of
play) × 2 (mates changed each time) Zagoruiko, named after a Russian pioneer of the
1940s.
A. Slesarenko
The Problemist, 2002
Mate in 2

  
Set play:  Try play: 1.Qa1?  Actual play: 1.Qh7! (threat 2.Qe4#) 
1...Kc4 2.Se5;  (threat 2.Qxa2#)  1...Kc4 2.Sxb6; 
1...Ke6 2.Sd4  1...Kc4 2.Qd4;  1...Ke6 2.Qf5; 
 1...Ke6 2.Qe5;  Byplay 
 but 1...b5  1...g6 2.Qxf7; 
 (freeing c6)  1...f5 2.Qg8. 
 refutes the try.  

(7) Bizarre Problems
What does an outandout chess player make of Ian Shanahan's weird problem? There are
three threatened mates, ABC. The seven different moves at Black's disposal (including
underpromotions of the black Pawn) lead to every combination of ABC. Is combinative
separation of threats too outlandish for you? Mathematics and chess are bedfellows indeed!
I. Shanahan
The Problemist Supplement, 2001
Mate in 2

Key 1.Bh5!
(threats 2.Qxe3 A and 2.Qg4 B and 2.Qf3 C)
1...Rh1 2.ABC;
1...g1S 2.AB;
1...g1R 2.AC;
1...g1B 2.BC;
1...Ke4 2.A;
1...Kg3 2.B;
1...g1Q 2.C.

