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White is to play and mate in two moves. Have a go at solving this first and then, when
you are ready, click the button below to see the solution and a commentary explaining
what the problem is all about.
Moves of bRh2 and bRg1 up the “h” and “g” files respectively are
set with shut-off mates delivered by the B+R battery. However, the moves of the bRs
along the first and second ranks lack provision. More importantly as things stand in the
diagram there are no mates arranged for the strong black defences, 1...Kf6 and 1...exf3.
This suggests that White should consider a move by wBf5. Try 1.Bg4?-A (>2.Rf5)
If 1...Rf2 2.Qh5-C (1...exf3 2.Re3) but 1...Rf1!-a refutes. Try 1.Bh3?-B (2.Rf5).
If 1...Rf1 2.Qh5-C but 1...Rf2!-b refutes. Key 1.Qh5!-C (-) If 1...Rf1-a 2.Bh3-B or
1...Rf2-b 2.Bg4-A. We can observe an alphabetical pattern; 1.A? a! 1.B? b! and 1.Key!
1...a/b 2.B/A. This defines the Banny theme, named after the Russian composer, Dmitri
Banny. The theme is enhanced in this problem by the transfer of the move, Qh5-C. It
will be seen that moves A, B and C all occur as white 1st moves (tries and key) and
2nd move mates. There is additional play: 1...Kf6/bxc3/e3(exf3) 2.Bxe4/Bxc3/R(c)(x)e3 but
the most important by-play is provided by the bRs.
1...Rxh5/Rb2/Rhg2/Rhh1/Rg5/Rxa1/Rgh1/Rgg2 2.Rc1/Bg4/Bg4/Rc1/Rc2/Bh3/Bh3/Rc2. The bRs are
said to occupy focal positions controlling both the diagonal and orthogonal white
batteries. When one black rook relinquishes its hold of one battery, the line of the
other black rook is cut by White’s mating move. The moves 1...Rhg2/Rhh1/Rgh1/Rgg2 are
particularly thought provoking. One bR hides behind the other and in this way complete
accuracy of play is achieved. This device is known as the Mackenzie theme. Arthur Ford
Mackenzie made many examples of his theme but he knew that this one was special. At the
time this problem was composed, tries were viewed merely as distractions to make the
solver’s task more difficult. The judge referred to the tries in his report as though
they were an integral part of the content – precisely Mackenzie’s intention.
Dmitri Banny was not the originator of this idea; his role was that of populariser.