Chessville - Bristol - Chess Problems and Compositions in Peter's Problem World with FIDE Master of Chess Composition Peter Wong - chess problems, chess compositions, chess puzzles, chess tactics, chess studies, chess endings, chess endgames

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Bristol
Peter's Problem World with FIDE Master of Chess Composition Peter Wong

New terms introduced here are also added to Peter's Glossary of Chess Problem Terms.

Many problem themes focus on the power of long-range pieces that act on lines, such as the battery (lines are opened by discovery), and the Grimshaw (lines are closed due to self-interferences).

Another strategic idea based on line play is line clearance. Take two similar line-pieces of the same color – e.g. two rooks, or a queen and a bishop – and move one of them along a line so that the other can follow along the same line. The first piece ‘clears’ the line for the second and, in particular, crosses over a critical square which becomes accessible to the following piece.

This manoeuvre is known as a Bristol clearance.

Mate in 2

67. Frank Healey
Bristol Tourney 1861
1st Prize

Mate in 3

Problem 67 is the famous three-mover that originated the idea. (The theme acquired its name after this composition gained a first prize in a tourney held in Bristol.)

Short mates in one move are set for 1…N-any (2.Qd6) and 1…Ba6/Bc6 (2.Qc6), but White has to deal with 1…Bd7/Be8.

The only way is 1.Rh1! (waiting), a spectacular key that passes over the critical square g1. Now 1…Bd7/Be8 is answered by 2.Qb1 (threat: 3.Qb4) Bb5 3.Qg1.

The key-rook in this problem serves no function other than to clear the first rank (the piece becomes redundant after moving), making this a pure rendering of the Bristol theme.

Though a principle of good problem construction holds that each piece should be utilised fully, preferably by having more than one function, a line-clearing piece is an exception to this rule and such “purity of aim” may be seen as a desirable feature.

In Problem 68, the white bishop on the long diagonal makes a series of impure, but thematic, Bristol tries. The clearances are not completely pure because the bishop, in crossing c3 to threaten 2.Qc3, also acts as a guard on that square.

The first try, 1.Bd4?, fails to 1…Ne4!. 1.Be5? provides for 1…Ne4 with 2.Qd4, but the bishop in blocking e5 admits the refutation 1…Be1! (since 2.Ne5 is now illegal).

Two more tries hinder the white rooks: 1.Bf6? Nb5! (2.Rc6 illegal), and 1.Bg7? Qf6! (2.Rc7 illegal).

The non-obstructive 1.Bh8! is hence correct, giving 1…Ne4 2.Qd4, 1…Be1 2.Ne5, 1…Nb5 2.Rc6, 1…Qf6 2.Rc7, 1…c1(Q)/(N)+ 2.Qxc1, and 1…d4 2.Be6.

68. Herbert Ahues
Mat Theme Tourney 1984
3rd Prize

Mate in 2

69. Milan Vukcevich
Probleemblad 1970
4th Hon. Mention

Mate in 3

In Problem 69, the key 1.g4! creates a thematic threat that nicely complements the main variations. The threat is the clearance 2.Ra8 and 3.Qb8. Black defends by activating the b2-bishop, aiming to interpose the piece on d6 via a3 or b4. Three such defences enable White to carry out more Bristol play along the e-file.

1…Rb3 shuts off the a2-bishop and lets White play 2.Re4 and 3.Qe5, since 2…dxe4 no longer checks White. (In all variations, the black knight is paralysed by the need to prevent Ngf3 mate.) 1…Rc3 interferes with the other bishop and permits 2.Re3 and 3.Qe5, since now 2…dxe3 is useless against the queen mate. Lastly 1…Bc3 cuts off the black rook, allowing 2.Re2 because once again the capture of the rook, 2…dxe2, does not stop 3.Qe5.

A helpmate with two phases is typically unified through White playing analogously across the two solutions, and Black doing likewise.

Problem 70, however, achieves harmony through reciprocal play between Black and White instead.

Part (a) of this twin is solved by 1.Bf5 dxe6 2.Qe4 dxe7, and part (b) by 1.exd6 Rf7 2.exd5 Qe7.

We find a black Bristol and white double pawn captures in (a), and a white Bristol and black double pawn captures in (b).

70. Valery Evdokimov
The Problemist 1991
Commendation

Helpmate in 2
(b) Kf7 to c3

71. Krassimir Gandev
Bulgaria vs. Romania Match 1975
1st Place

Helpmate in 2
2 solutions

Every move appears as part of a Bristol manoeuvre in the highly intensive 71.

The solutions are 1.Qe4 Rh1 2.Bf5 Qg1 and 1.Rf2 c4 2.R8f5 Rc3.

Both White clearances are pure, including 1…c4 which illustrates the ability of a pawn, on its initial square, to act like a line-piece.

In relation to the point made earlier on how well-constructed problems utilise the pieces fully, notice the functions of the thematic pieces when they don’t play the Bristol moves. The white pawn guards d3 in one solution, while the white queen guards e4 in the other.

Each pair of black line-pieces, when stationary, are also essential for controlling the prospective White mate, to force the interference on f5.

Have a go at solving Problem 72, which features a thematic try with changed variations between the try play and actual play.

The solution will appear next month.

72. Miodrag Mladenovic
Mat Theme Tourney 1984
2nd Prize