Yorkshire Chess History

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Crosskill’s Over-50-Move Ending

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The Chess Player’s Magazine Vol. II, 1864, pp.305-311 gave the following position with analysis by Alfred Crosskill.

At the time it was believed there might exist positions where wins could be forced, but required more than the 50 moves allowed in the rules. Arthur Crosskill sought to specify such a position, with supporting analysis. Though positions with K+R+B versus K+R are drawn in the general case, there are positions where the extra Bishop leads to a win.

In this position Black’s King is crucially corralled in a corner of the same colour as White’s bishop. The article started as follows:

THE ROOK AND BISHOP AGAINST ROOK.

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BLACK.

WHITE.

White having to play first can win the game, but requires 64 moves if Black makes the best defence.

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TO THE EDITOR OF THE “CHESS PLAYER’S MAGAZINE”

The April number of the Chess Player’s Magazine contained a paragraph calling attention to some new rules adopted by the chess club recently established in Hanover with reference to the 50 moves usually allowed for bringing certain end-games to a conclusion. That the old law fixing that number is not sufficient to meet all cases has long been the opinion of many experienced players, and the foregoing position is a good illustration of its correctness, for although White has undoubtedly a forced won game, he cannot against the correct defence win the adverse Rook in less than 56 moves, and requires then 8 more moves to give checkmate.

It would be impossible within the limits of the Chess Player’s Magazine to give all variations on Black’s moves, or to prove exhaustively that White’s attack is carried on in the best manner possible; but Herr Kling, who is one of the highest living authority on this branch of chess science, is, after carefully examining the analysis, of opinion that White has no quicker way of winning.

The article ended with Crosskill’s skeletal summary analysis. The reader needed a moderate degree of ability to flesh out some of the variations. The published analysis (here converted to algebraic notation and re-formatted) ran as follows:

1	Be3 If 1. Be5 then 1. ... Ra6+ 2. Kf7 Kh7 draws.	Rd1 If 1. ... Ra6+ then 2. Kf7 as at move 10 below. If 1. ... Rd6 [sic; means 1. ... Re8 perhaps] then 2. Bd4 and wins. If 1. ... Kg8 then 2. Rb8+ Kh7 3. Bd4 and wins. If anything else then 2. Kg6 and wins.
2	Bc5	Rd3 If 2. ... Rd2 then 3. Rb3 and wins. If 2. ... Re1 then 3. Bd4 and wins. If anything else then 3. Kg6 and wins.
3	Be7	Kg8 If 3. ... Rg3 then 4. Bd6 Rg7 5. Rb2 Kg8 6. Be5 and wins.
4	Rb4	Rg3 If 4. ... Rf3+ then 5. Kg6 Rg3+ 6. Bg5 Rf3 7. Bf4 and wins.
5	Bd6	Rg2 If 5. ...Rg1 then 6. Rb8+ Kh7 7. Rb7+ Kg8 8. Be5 and wins.
6	Bf4 A position like this, but with White’s Rook at a4 instead of b4 occurs again after White’s 17th move. If instead White tries 6. Rb8+ then after 6. ... Kh7 7. Rb7+ Black draws by 7. ... Kh6 because White cannot win Black’s Rook by 8. Bf4+ &c, as he would do if the Rook was at g1.	Ra2
7	Rb8+	Kh7
8	Rb7+	Kh8 If 8. ... Kg8 then 9. Rg7+ Kh8 10. Rg1 Kh7 11. Be3 Rc2 12. Bd4 as at move 37.
9	Be3	Ra6+
10	Kf7	Rc6 If 10. ... Rd6 then 10. Bg5 and wins. If anything else then 11. Rb1 wins.
11	Ra7	Kh7 If 11. ... Rc2 then 12. Bd4+ Kh7 13. Kf6+ and wins. If 11. ... Rc8 then 12. Bf4 and wins. If anything else then 12. Bg5 and wins.
12	Rd7	Rc8 If 12. ... Rc2 or Rc3 then 13. Bf4 and wins. If 12. ... Rc4 then 13. Kf6+ Kg8 14. Rd8+ Kh7 15. Bd4 and wins.
13	Bg5	Rb8 If 13. ... Ra8 then 14. Kf6+ Kg8 15. Kg6 Kf8 16. Rf7+ Ke8 17. Re7+ Kf8 18. Re6 and wins.
14	Rd1 If instead White tries 14. Kf6+ &c., which wins when Black’s Rook is on a8, the game is drawn, because Black can safely play 17. ... Kd8	Rb7+
15	Be7	Rb6
16	Bd6	Rb7+ If 16. ... Kh6 17. Rd5 Rb7+ 18. Be7 Ra7 19. Rb5 and wins.
17	Kf6 The pieces are now in the same position as after White’s 6th move, except that White’s Rook is here at d1 instead of d2, which prevents Black from prolonging the game by 17. ... Rb1.	Rb6 He has the choice of playing either 17. ... Rb3, or 17. ... Rb6, which both lead to the same result.
18	Rh1+	Kg8
19	Rg1+	Kh7
20	Rg7+	Kh8 If 20. ... Kh6 then 21. Rd7 and wins easily.
21	Rd7	Rb2 If 21. ... Rb1 then 22. Bc5 Rb3 23. Bd5 and wins.
22	Bc5	Rc2 If 22. ... Rb1 or 22. ... Rb5 or 22. ... Rb8 then 23. Kg6 and wins. If anything else then 23. Bd4 and wins.
23	Rd5 If 23. Bd4 then 23. ... Rc6+ 24. Kf7+ Kh7 and White must play 25. Be3 reaching the same position as after 12. Rd7.	Rc3
24	Bd6	Kg8 If 24. ... Kh7 then 25. Rh5+ as at move 26. If 24. ... Rb3 then 25. Kf7 Rf3+. 26. Kg6 and wins.
25	Rg5+	Kh7
26	Rh5+ If 26. Rg7+ then 26. ... Kh8 27. Rd7 Rc2 28. Be5 Kg8 gives Black the same result given below.	Kg8
27	Be5	Rb3 If 27. ... Ra3 then 28. Kg6 Kf8 29. Bd6+ Kg8 30. Rc5 and soon wins. If 27. ... Rc6+ then 28. Ke7 Rh6 29. Rh4+ [sic, means 29. Rg5+] and mates in six moves (see Handbook, p.467.)
28	Rg5+ If 28. Bd4 then Black prolongs the game by 28. ... Rb7.	Kh7 If 28. ... Kf8 then 29. Bd6+ Ke8 30. Ke6 and wins.
29	Rg7+	Kh8 If 29. ... Kh6 then 30. Bf4+ and wins.
30	Ra7	Rb6+
31	Kf7+	Kh7
32	Bf4 The position is now similar to that after White’s 12th move, and would be drawn if White had to play first.	Rb4 If 32. ... Rb6 or 32. ... Rb7 or 32. ... Rb8 then 33. Ra6 Rb7+ 34. Kf8 and wins.
33	Kf6+	Kg8
34	Ra8+	Kh7
35	Be5	Rb1 If 35. ... Rg4 then 36. Ra1 wins.
36	Ra7+	Kg8 If 36. ... Kh6 then 37. Bf4+ Kh5 38. Kf5 and wins.
37	Bd4	Rf1+ If 37. ... Re1 or 37. ...Rc1 then 38. Ra8+ Kh7 39. Kf5 and wins. If. 37. ...Rd1 then 38. Ra8+ Kh7 39. Rd8 and wins. If 37. ... Rb3 then 38. Ke6 with an easily-won game. If 37. ...Rb5 then 38. Kg6 Kf8 39. Bf6 Ke8 40. Re7+ Kf8 41. Rd7 Rb8 42. Rh7 and wins Rook.
38	Ke6	Rf7 If 38. ... Rf8 then 39. Rg7+ Kh8 40. Rc7+ Kg8 41. Be5 Re8+ 42. Kf5 and soon wins Rook.
39	Ra1	Rf8 If 39. ... Rf5 then 40. Be5 and wins. If 39. ... Rb7 or 39. ... Rc7 then 40. Ra8+ Kh7 41. Kf5 and wins.
40	Rh1	Re8+
41	Kf6	Re2 If 41. ... Rd8 then 42. Be5 with a won position.
42	Rg1+	Kf8 If 42. ... Kh7 then 43. Kf7, as in last note to move 37.
43	Be5	Rf2+
44	Ke6	Ke8
It is now a variety of the celebrated “Philidor” position, a complete analysis of which is given in Mr. Staunton’s Handbook, pp. 449, 450, and 451, so that further notes to the moves below are not necessary.
45	Ra1	Rd2
46	Ra7	Rd1
47	Rg7	Rf1
48	Bg3	Rf3
49	Bd6	Re3+
50	Be5	Rf3
51	Re7+	Kf8
52	Ra7	Kg8
53	Rg7+	Kf8
54	Rg4	Re3
55	Rh4	Rxe5+
56	Kxe5	Kf7
57	Rg4	Ke7
58	Rg7+	Kf8
59	Rd7	Ke8
60	Ke6	Kf8
61	Kf6	Kg8
62	Rd8+	Kh7
63	Ra8	Kh6
64	Rh8 and mates

Ken Whyld’s Oxford Encyclopedia of Chess quotes the position as a left-right mirror image of the original, and gives a 57-move main line (with no variations) diverging from the above at White’s 39th move, as follows (inverting files back to match the above):

39. Rg7+ Kh8 40. Rc7+ Kg8 41. Be5 Rf2 42. Rg7+ Kf8 43. Rh7 Ke8 44. Rc7 Rd2 45. Rb7 Rd1 46. Rg7 Rf1 47. Bg3 Rf3 48. Bd6 Re3+
49. Be5 Rf3 50. Re7+ Kf8 51. Rc7 Kg8 52. Rg7+ Kf8 53. Rg4 Ke8 54. Bf4 Kf8 55. Bd6+ Ke8 56. Rg8+ Rf8 57. Rxf8#.

Whyld’s line was probably a computer-generated improvement, though he doesn’t say so.

Created

30/12/2012

Last Updated

01/01/2013