(From Mat Plus No.1, Spring 1994, p.11)
If somebody wants to explore and elaborate certain theme as old as Bristol clearence, he is obliged to an analytical and systematic approach. Such was the approach Miroslav Stošić (1949-1975) had to Bristol theme in modern twomover. His intention was to examine which of all possible combinations of Bristol and anti-Bristol effects in multiphase twomover it were possible to combine with typical elements of virtual twomover, such as changed mates and/or defenses, corrective motifs etc. Unfortunately, tragically early death terminated his work before it had been completed. The minimal requirement assumed by Stošić was: two phases with Bristol and/or anti-Bristol opening move. If this is accomplished with only two thematic men then either one of them will two or more times clear or 'un-clear' one and the same line to the other piece, or they will alternatively clear or block line to each other. If more than two thematic pieces are involved and consequently two thematic systems are required, Stošić introduced the additional condition: systems must be linked by one thematic piece used in both (or all) of them. This minimizes the danger of loosing the organic connection between two (or more) systems. It would be ambitious and wrong to declare that Stošić is the first one who made attempts with multiphase Bristols. There had been a lot of such attempts, but mostly incidental or narrow-minded 'one-timers' like article by F. Dumel: "The Choice of Line Clearance" in Problem 112-119 (1967) which is limited to only one form of theme: clearence of two different lines of the same white piece. The importance of Stošić's work is before all in a systematic and universal approach. Considering requirements and conditions mentioned above Stošić recognized 15 elementary forms of the theme. They are listed in the table. Of course, total number of possible forms is greater, but all of them are either extensions or combinations of the elementary forms.
As already mentioned, Stošić had time for early attempts only. There were a lot of work-schemes in his notebook, even few completed problems probably not quite satisfactory for his standards and therefore unpublished. Some of these are originally published in the collection of Stošić's problems (printed 1979) and reproduced here (Nos. 2, 5, 7).
No.1 shows form I: R clears the line for Q along 3rd row in different lengths: 1. Rd3? (2. Qc3#) e3!, 1. Rf3? e3 2. Q:e3# 1. ... Sf6!, 1. Rh3! Sf6 2.Qg3#. Stošić's opinion was that more effective would be reversed style: gradual, from one try to another, reduction of the cleared line size combined with corrective effects to enable substitution of the lost "Bristol" mates by the new ones. A simple position No.1a is an illustration: 1. Rg8? (2. Qg5#) Sg7 2. Q:g7# 1. ... Be6!, 1. Rg6! Sg7, Be6 2. Bf6, R:e6#. It should be mentioned that this is an extreme reduction of a very complex unfinished position from the Stošić's notebook.
Example No.2 displays form III with white R-R anti-Bristol and Bristol. 1. R5d3? Rb4! 2. R2d4?, 1. Rd7 (2. Qf4#) B:c7 2. R2d6#. Other variations are 1. ... Rb4 2. R2d4# and 1. ... Qb8 2. Rh7# with changed set mate (2. Qg7#). The form IV is shown in No.3 with 3 changes between try and actual play: 1. Qh1? gf4, Kf5, f5 2. Rg1, Qe4, Rh6# 1. ... g4!, 1. Ra1 gf4, Kf5, f5 2. Qg4, Qb1, Ra6#. A wonderful combination of the classical and modern style! The antiform of previous complex is form V, presented in No.4. There are two thematic mates set: 1. ... Sc4, Re3 2. R:c4, Qc6#. Each of them is alternatively eliminated by anti-Bristol tries: 1. Qc5? Sc4! 2. Rc4? and 1. Rc5? Re3! 2. Qc6?. The key move 1. Bc5! (2. Sd6#) surprisingly changes both set mates: 1. Sc4, Re3 2. Q:c4, Q:e3#.
In twomover No.5 form VII is used: 1. R4d2? e3 2. Qd3# (1. ... Sd5 2. Q:d5#) 1. ... Qc7! with Rd4-Q Bristol; 1. Rd6 Sd5 2. R1:d5# with Rd4-Rd1 Bristol. Note that, since at the same time key move is R-Q anti-Bristol, this problem shows form III, as well. Two anti-Bristols in No.6 complete the form VIII. Flight-giving tries are: 1. Re3? Qg7! 2. e4? and 1. Re7? Be6! 2. Qe6?. Key move 1. Re6 also releases the BK flight. Problem No.7 showing form IX is the last entry on Bristol theme in Stošić's notes. Try 1. Rb3? d3! 2. Qc3? shows R-Q anti-Bristol. In the solution 1. Rf6 g5 2. R2f5# appears R-R Bristol. As it can be seen, Stošić's interest in Bristol
twomovers, though brutally terminated at early stage, gave excellent
results which predict a lot of hidden possibilities. It is evident
that introductory moves are not necessarily pure Bristol refuges and
often bear side purpose. Let me quote a part of the comment on here
reproduced composition No.3 from the collection
Twomover No.8 from already mentioned Dumel's article exhibits form X: 1. Ba6? ~, Sb6 2. Qc4, Qb5# 1. ... d3!, 1. Re6! ~,Sg6 2. Qe5, Qe4#. Bristol clearances are used in two mates (threats + variations) both in try and actual play. More than a half of century old No.9 shows form XI expanded to three thematic tries: 1. Ra5? c4! 2. Qa2?, 1. Rd7? b6! 2. Qf7? and 1. Bb6? e4! 2. Qd4?. The key is 1. Rh1 with the block position. It is possible that there are existing problems for some of elementary forms not illustrated here (II, VI, XII, XIII, XIV and XV), and it is certainly possible to create a plenty of good compositions in some of either elementary or more complex textures. Let us hope that one theme tourney will approve it. *** Yes,
1st Pr. [10]: 1. B:e3? ~, Qf1, Se6, Sc5 2. Bf4, Qd4, R:e6, Qc5#, 1. ... Sd6!. 1. R:f6! ~, Qf1, Se6, S:c5 2. Rf5, Bd4, Q:e6, Qd6#. The most harmonious problem of the tourney: three changed mates between try and actual play with strategically analogous first moves. It should be mentioned that the purity of aim has not been of great significance in my estimation of the entries. 2nd Pr. [11]: 1. Ra8? ~, d4, Qh6, Se4 2. Qb8, Ra5, f4, Sf3#, 1. ... bc3!. 1. Rf3! ~, d4, Qh6, Se4 2. Qf6, Rc5, Qf4, Sf7#. An elegant and thematically stronger achievement than the 1st Prize winner, also with three changes between the try and solution, but with unbalanced contents in two phases. However, a concurrent try 1. Rc6? is noticeable inconveniance. 3rd Pr. [12]: 1. Bd4? Se4!; 1. Be5? Be1!; 1. Bf6? Sb5!; 1. Bg7? Qf6!. 1. Bh8! ~, Se4, Be1, Sb5, Qf6 2. Qc3, Qd4, Rc6, Rc7#. Since 1. Bd4? is not sufficiently long clearence, B has to select one of the destinations in the North-East part of the board. A beautifully constructed problem. 4th Pr. [13]: 1. Rb2? ~, Qc4, Kd5 2. Rgc2, Se7, Rgc2#, 1. ... Qf8!. 1. Qg7 ~, Qd5, Kd5, Qf6 2. Rg6, Qc7, Rg4, Qd7#. The most exciting in this twomover is the fact that white Bristol attacks are defeated by black Bristol moves. It is a pity that Rf2 has no role after the key, and that after 1. ... Kd5 in try play white responds with threatened mate.
1st H.M. [14]: 1. Re6? ~, Qh2, Sc4, Sc3, de6 2. Q/Rd6, e4, Rcd3, Se3, Qe6#, 1. ... Sb5!. 1. Rc6 ~, Qh2, Sc4, Sb5, Se3, dc6 2. Qd6, Qe4, Red3, c4, Se3, Qe6#. Two changed and two transferred mates in try and real play make a very rich composition. It is a pity that the try is thematically stronger phase. 2nd H.M. [15]: 1. Rh6? ~, Bg8, Rd2!2. Qc6, Qg6, ? #; 1. Rd6!? Rd2,Bg8! 2. Sfg5, ? #; 1. Rg6!? Rd2, Bg8! 2. Rg4, ? #. 1. Rf6! ~, Rd2, Bg8 2. Qc6, Shg5, Bf5#. A masterly constructed problem with corrective play. 1. Rg6? and 1. Rd6? correct the longest Bristol until h6, and all of above is corrected further by the key move. However, the similarity with Stošić's problem and attached scheme is not in favor to the originality of this achievement. 3rd HM [16]: 1. Be4? Rf4! 2. Qd5?; 1. Rd2? Sf4! 2. Qb2?. 1. Rg8! ~, Rg3, Sg3 2. Qg7, Qd5, Qb2# (1. ... Re7, Re3 2. Ra4, Qd5#). Two anti-Bristol tries and Bristol key. Harmonious contents but technically unpolished position. 4th H.M. [17]: (1. Bb8? Bc7!) 1. Bd6? ~, S~, Sd5 2. Qe5, Bc6, Sg3#, 1. ... Sd3! 1. Be5! ~, Sf~, Sd3, Sd5 2. Qf4, d3, cd3, Sd6#. What is interesting here is that shorter clearances are stronger than longer ones. Nevertheless, I would rather see flight-giving 1. Bd6 as the key move.
1st Comm. [18]: 1. Bc8? Ke4, Re4, g4!2. Qf5, Qd7, ? #. 1.Rga3 Ke4, R~, Re4 2. Qf3, Sc3, Qb3#. In spite of standard matrix for B-Q and R-Q clearence this problem with two changed mates (after BK-flight and BR correction) would have been among the prizewinners, if there is not a very unpleasant dual after 1. ... R~(7) in try play. It is worth of mentioning that the purity of aim is preserved for clearances in both phases! 2nd Comm. [19]: 1. Be6? ~, Qe5, Kd3 2. Qd5, Sf2, Bf5#, 1. ... Rd3!. 1. Bf7! ~, Qf4, Rf3, Kf3 2. Bg6, Qd5, Qc4, Bd5#. Spectacular first moves in both phases. However, although BK flight to f4 in actual play is not a defense, the possibility for the second mate 2. Bd5# is a noticeable flow. 3rd Comm. [20]: 1. Rg8? Kf6, Kf4, f4 2. Qg7, Qg3, Qg5#, 1. ... Kd5!. 1. Bb6! ~, Kf4, Kf6, Kd5 2. Qd4, Qe3, Bd4, Qc5#. Two phases with a plenty of thematic mates, but again actual play is inferior phase. Furthermore, mate on c5 is not clear Bristol-mate since WB removes BP which guards that square. Spec. Comm. [21]: a) 1. Rd3 cb4, S~, Se4 2. Qd4, Re3, Sd7#. b) 1. Rd6 cb4, S~ 2. d4, Re6#. Strictly thinking, this problem should be considered as unthematic because it presents two single-phase, rather than single multiphase twomover. Yet, since twins are recognized as multiphase problems, this original and effective prolonged problem deserves commendation. |