Günther Weeth 75 JT C 31.7.2011 - announcement

1.Qb5 Gb4 2.Qc4 Gd4(b) 3.Qe6(w) Qd7 4.Gd8 Qc8+ 5.Gb8 Qa6#

Two round trips ending with colours of pieces reversed. While grasshopper makes a rectangle, the queen goes around the square, but stops on 6 squares instead of only 4 corners.

1.Bc7(w) Bb8 2.Rc7(w) f5 3.Ke5 Rc4#

1.Rc7(w) Rc8 2.Bc7(w) Ka5 3.Kc5 Be5#

Not exactly critical black moves followed by black interference on c7. Rather it is necessary to stop at c7 for acquiring the white colour and getting the inversion of B1 and B2 moves in the process. Pity that wK move does not allow bK move to c5, that would be even more analogous.

1.d4(b)! d3 2.a4 d2(w) 3.d4(b) d3 4.a5 d2(w) 5.d4(b) d3 6.a6 d2(w) 7.d4(b) d3 8.a7 d2(w) 9.d4(b) d3 10.a8Q d2(w) 11.d4(b) d3 12.Qf3 d2(w) 13.Rd4(b)+ Rg4 14.Bh4 Kxh4 15.Qxh6+ Sxh6#

The mechanism involving two magic squares and a double-step of white pawn yields one free move for white every two moves overall. After a queen promotion, the rest is still slightly magical: wR must turn to black for the appropriate guarding.

1.Kd6! zz
1...Sf7(w) 2.Rc1 Bxf7(w) 3.Bc4#
1...Bf7(w) 2.Re1 Sxf7(w) 3.Se5#

Another example of black reciprocal moves to the same magic square (compare to h#3 above. The difference is that white does not move away, rather leaves the piece to be captures and makes anti-critical move by the right rook in the anticipation of the following capture.

1.Bc6? th. 2.Qe6# A (2.Qc8?)
1...Rxb5! a

1.e6? th. 2.Qc8# B (2.Qe6??)
1...Qxb5! b

1.Rh3! th. 2.Sb2#
1...Rxb5 a 2.Qc8# B (2.Qe6+ Rd5!)
1...Qxb5 b 2.Qe6# A (2.Qc8+ Qc6!)

Here the role of two magic squares is different from previous four problems. Instead of their active use for colour changes, they are used to prevent moves of some pieces to them because of the self-check. Black queen cannot go move any of them (but it has access to c6 from b5), while black rook can go to d5, but not c5.

The strategy for "Dombrovskis" is easy. In tries white guards additionally b5 to threat queen mate(s), but one mate is impossible by white error and the other is successfully defended by the right capture on b5. In solution another mate is threatened (by knight), and captures become blocks with dual avoidance as stated.

Why then "Dombrovskis", not Dombrovskis? Simply because the solution variations are prepared already in the set play and the key brings nothing new. This feature is shared by many problems claiming to show Dombrovskis, but generally frowned upon by certain experts of move function changes in twomover.

So we have two important roles of magic squares: getting valuable material for one of sides (in problems 1-4 so far) and avoidance of some moves (in this problem). Note that my own h#3 already quoted above uses both of them: c3 and d1 as source of white pieces, while e3 is used as prevention of cooks with wQe3# impossible.

Note also that this problem is the only with substantial number and quality of pieces on both sides, all other cited problem have one of sides strongly constrained.

1.Rb5? zz
1...Gc8(w) a 2.Ga8# A
1...Gc4(w) b 2.Ga6# B
1...Gc6(w) c 2.Ga4# C
1...e1G(w)!

1.Kb7! zz
1...Gc8(w) a 2.Ga6# B
1...Gc4(w) b 2.Ga4# C
1...Gc6(w) c 2.Ga8# A
1...e1G(w) 2.Ga5#
1...e1B(w) 2.Bc3#
1...e1S(w) 2.Sc2#

Three main variations of solution and the try present well known Lacny cycle, based on the known geometry. The 6 lines have 2 intersections, allowing complete switch three to three by moves of two pieces from lines to intersections. By chance (or rather thanks to author's decision) the arrival squares of defences are magic and newly appearing wG proceeds to mate on a-file.

1.f1Q 2.Qf7 3.Qd5(w) Qb7=

1.f1R 2.Rf5 3.Rd5(w) Rdd1=

1.f1B 2.Bc4 3.Bd5(w) Ba2=

1.f1S 2.Se3 3.Sd5(w) Sc3=

What is needed for stalemate? Firstly it is necessary to guard b1. Secondly Black wants to get rid of the pawn. Both aims can be reached by promoting the pawn and moving to d5. Four promotions, four ways to d5 and four final moves to four different squares. Very economical and easy to understand.

1.Kg1 c8S 2.Kh2 Se7(b) 3.Sf5 g4 4.Sg3 g5 5.Sh1 g6(b) 6.g5 f4 7.g4 f5 8.g3 f6(b) 9.f5 d4 10.f4 d5 11.f3 d6 12.f2 d7(b) 13.d5+ Kd3 14.d4 Ke2 15.d3+ Kf1==

Finally there is another, even more unusual aim: double stalemate. There are four magic squares on the board and each of them is used exactly once. As a result of a single sequence, pawns d3, f2 and g3 are turned to black, already hinting the cage for both kings. It is further stuffed by bS born from wPc7. Again it is black who is always short of moves and White must provide him new and new units to move with.