|
The Middle Shogi Manual was compiled by the late George Hodges
This website lists some new insights into these problems
|
All problems were fed to the HaChu engine. This was running in tsume mode with the 'Allow repeats' setting, which puts the obligation to deviate always on the checking side. For problems where promotion played a crucial role, solution was attempted with both 'Promote on entry' switched off (which means that HaChu plays according to the rule that a piece that deferred promotion can promote on later moves that touch the zone, but not on the turn immediately following their deferral, unless they capture), as well as on (which means non-captures can only promote when the enter the zone from without). Note that both of these rules are different from what the Middle Shogi Manual states, where the condition is that the next move with that piece cannot be a promotion.
The problems of the C series came without historic solutions, and the solutions presented in the MSM were found in recent times. Many problems so far defied solution, however. As the HaChu analysis shows, this sometimes is because the problems are flawed, so that no solution exists under the rules as we know them (or, in case of promotions, were assumed in the MSM). In many other cases HaChu did manage to find a solution, though. First we discuss these hitherto unsolved problems.
D6 - The published mate assumes the Gold can promote on an in-zone non-capture. If that were the case, 1. FKx9d +VMx9d 2. Lnx9fx8e +VMx8e 3. G-4c+ +RC-6c 4. +Gx6c K-11b 5. +Gx11c K-10a 6. +L-9b Kx9b 7. DHx7b+ K-9a 8. +DHx10b Kx10b 9. DK-9c+ K-10a 10. +G-11a mate would be faster. In addition, the DH at 6i would be a redundant 'spectator'. Without such promotions, 3. G-6b= +RCx2c 4. DH-6c+ +Lx6c 5. Gx6c+ BT-9c 6. +Gx9c K-10b 7. Ky-12d+ +SMx12c 8. +Lx12c K-11a 9. +G-11c Ky-11b 10. +L-9c K-10a 11. DH-4g +VM-7d 12. DHx7d+ Ky-9d 13. +DHx9d mate is necessary.
D7 - The Forsyth notation has the FL of the wrong color! The published, embarrasingly simple solution promotes a GB on an in-zone non-capture, and does not need any of the pieces on the left half of the board. With promote-on-entry rules, the problem becomes a far more difficult mate in 15:
1. FLx5e Phx5e 2. +L-3b Kx3b 3. GB-4c= K-3c 4. P-2d+ Kx2d 5. Rx1d+ K-3c 6. Ky-4d+ FKx4d 7. GBx4d+ Kx4d 8. +Rx3d K-5c 9. +R-4c K-6d 10. +BT-7d+ +Lx7d 11. +R-6c K-7e 12. +Rx7d K-8f 13. +R-8e K-9g 14. +GB-10g Rx10g 15. +R-9f mate
which does use all pieces, and obviously must be the intended solution.
D8 - Forsyth notation has vm in stead of +vm, otherwise OK
D9 - Without promoting on in-zone non-captures this is a bit more challenging: 1. Ky-1c+ FKx1c 2. Phx1c= K-2a 3. +DKx5d-4c +DKx!4c (3... +DKx4c-5d 4. +FLx5d +FLx5d 5. Ph-3a= Kx3a 6. BT-2c= R-3i 7. +DKx3i +R-3h 8. +DKx3h K-2a 9. P-1a+ Kx1a 10. +DK-3a +FL-2a 11. +DK-3c mate) 4. Ph-3a= Kx3a 5. BT-4b= K-2b (5... K-4b 6. +DKx3b K-5c [6... Kx5a 7. +DK-3c K-5b 8. +DK-4c K-5a 9. +P-6a mate] 7. +DK-4c K-6d 8. +DK-5d K-7e 9. +DK-6e K-8f 10. Ln-10h +Phx10h 11. +DK-9e mate) 6. BTx3b+ K-1c 7. +DK-3c +R-2c 8. +BT-2b K-1d 9. +FL-9l +RC-7j 10. +FLx7j R-6i 11. +FLx6i +R-2e 12. +BT-1c mate All sente pieces are essential to this solution, delete any of them and there is no mate. (Even the Pawn on 4e serves to block a +FL.) So there is no doubt that this is the intended solution.
D13 - MSM OK, but many unused pieces. The intended solution is 1. Ky-7d+ BTx7d 2. +G-7h +GBx7h (2... +GB-7f/g 3. +Cx7f/-7g K-8e 4. +C-8f K-9d 5. BT-9c mate, or 2... K-8e 3. +C-8f K-9d 4. BT-9c mate) 3. +RC-7g Rx7g 4. R-5e= +SMx5e (4... BT-6e 5. +DK-7c K-8e 6. +C-8f K-9d 7. BT-9c mate, or 4... P-6e 5. Ph-5c+ K-8e 6. +C-8f K-9c 7. BT-9c mate) 5. Ph-5c= K-8e 6. +C-8f K-9d 7. BT-9c Kx9c 8. Ph-7e= K-10d 9. Ph-9c+ K-11d 10. +Lx11e BTx11e 11. +Phx11e Kx11e 12. +DK-11c K-12e 13. +Cx12f Kx12f 14. VMx12g Kx12g 15. VMx11g K-11h 16. VM-11h K-12i 17. VM-11i K-12j 18. VM-11j K-12k 19. VM-11k K-12l 20. VM-12k +VMx12k 21. +DK-11k mate The parasytic mate in 7 is possible because on the immediate 2. +RC-7g the +RC cannot be taken by the Rook yet, and taking it with the +GB leaves 7g unprotected, so that the +DK deliver an immediate mate there. This can be repaired by relocating the +DK to 2c, and putting a sente Pawn on 3d to prevent it wrecks havoc on the diagonal. After 2. +G-8h:
D14 - Mate in 14 1. +L-4b +RCx4b (1... Kx4b 2. +Cx3b K-4a 3. +DH-7a C-5a 4. +DHx5a Kx5a 5. Phx5d+ +RC-5c 6. +Ph-8a +RC-7a 7. +Phx7a mate or 1... BTx4b 2. +Cx4b Kx4b 3. Ph-3c+ K-4a 4. +DH-8a+ +RC-6 5. +DHx6a C-5a 6. +DHx5h mate) 2. Ph-3c+ Kx3c 3. +DHx1e Sx1e (3... K-4c 4. +DHx1d-1c BT-2c 5. +DHx2c K-4d 6. +Cx4b K-3e 7. +DH-1c mate or 3... K-4d 4. +C-2c BT-2b 5. +RCx2b K-3e 6. +DH-1c mate) 4. +C-2c Kx2c 5. C-1d= K-2d 6. +P-2e Kx2e 7. Cx1e+ K-2d 8. +C-2e Kx2e 9. +VM-1f K-2d 10. +VM-1e K-3e 11. +VM-1c K-2e 12. P-2f Kx2f 13. +VM-2d K-3g 14. +RC-1e mate
D15 - 1. +RC-11j +Kyx11j 2. DKx11j Kx11j 3. +FL-10j Kx10j 4. +L-9k Kx9k 5. +DK-8j Kx8j 6. +R-8g K-9k 7. +FL-5g +G-7i 8. +Rx8k K-10l 9. +RC-7i K-11l 10. +Rx10k Kx10k 11. +SM-7h +P-8i 12. +SMx8i R-9j+ 13. +SMx9j K-9l 14. +RC-9k mate After 4. +Lx9h:
D16 - Forsyth misses empty square between G and +FL
D18 - Faster (mate in 8) is: 4. +SM-3e Kx3e 5. +R-3c +FLx3c 6. Lnx6cx5d K-2d 7. Lnx4c K-1c 8. Lnx2c mate
D19 - Faster is 8. DKx10b FKx10b (8... BTx10b 9. Lx-10c mate) 9. Ln-11d K-12a 10. Ln-12c mate
D20 - Mate in 9: (+P-5a not needed) 1. +DHx7h +VMx7h 2. +DHx7h FKx7h 3. Ph-5e K-7f 4. +DKx7h K-8f 5. +DK-8g K-9e 6. +Rx10d Kx10d 7. +DK-10e K-11-c 8. +DK-12c K-10d 9. +P-10e mate
D21 - Impossible
D22 - Forsyth wrong color +C
D23 - Impossible
D25 - When non-captures leaving the zone can promote, this is a mate in 12: 1. BT-11e Kx11e (1... FKx11e 2. +Rx12h FK-12f 3. +Rx12f Kx12f 4. Lnx9i-10h K-12e 5. Ln-12g K-12d 6. Ph-10b= K-12c 7. Bx11b+ mate) 2. VMx10e= BTx10e (3... Gx10e 4. Rx10e BTx10e 5. Ln-10g K-10d 6. Lnx10e mate) 3. Ln-9g +Gx9g 4. Phx10f+ Phx10f 5. DKx12d+ Phx12d 6. Rx10e K-11d 7. +SM-12c FLx12c 8. Bx12c+ Kx12c 9. R-10c+ K-12b 10. +Rx12d K-11a 11. +R12d-11c K-12a 12. +R10c-11b mate. This nicely uses up all pieces, and so looks like the intended solution.
When non-captures can promote only on entering the zone, this solution is flawed, however. At first glance this is not obvious, as 4. Phx10f+ is a capture. The defense 4... Gx9g, however, which is very sub-optimal when the Phoenix can still promote on the evacuated square, (5. Rx10e K-11d 6. R-10d+ Kx10d 7. Ph-9g+ mate) completely thwarts the mate when such a promotion is forbidden! And there is no alternative; the problem has no solution under promote-on-entry rule.
D26 - Mate in 19 1. Rx2b+ +RCx2b (1... K-6a 2. +L-7b Kx7b 3. Rx10b+ +Bx10b 4. +Rx6b DHx6b 5. +DK-5d Kyx5d 6. +DHx5d K-6a 7. +DH-8a K-5b 8. +GB-4b K-4c 9. +DH-4e mate) 2. +GB-4b K-6a 3. +L-7b Kx7b (3... DEx7b 4. +DHx7b Kx7b 5. +DK12c-7c K-6a 6. +DKx6b-5a mate) 4. Rx10b+ +Bx10b (4... K-6a 5. +GB-5a K-5b 6. +Rx6b DHx6b [6... Sx6b 7. +GB-4b K-6a 8. B-7a+ mate] 7. +DK-5d Kyx5d 8. +DHx5d mate) 5. +DH-7c Sx7c (5... DEx7c 6. +DKx8d-9c K-6a 7. B-7a+ Kx7a 8. +DKx7c K-6a 9. +DKx6b-5a mate) 6. +DKx8e-9d K-6a (6... DEx9d and as in main line from move 8, or 6... K-7c 7. +DKx!8c S-8c 8. +DKx!8c +B-9c 9. +DK12cx9c +RC-8c +DK9cx8c mate) 7. +DKx8c-7b Kx7b 8. B-7a+ Kx7a 9. +DK-7c K-6a (9... SM-7b 10. +FLx4d mate) 10. +GB-5a K-5g 11. +GBx6b K-4a 12. +DK-5a K-3b 13. +DK-4b K-2c 14. +DKx2b K-3d 15. +DK-2d K-4e 16. +DKx4d K-5f 17. +DKx5e K-6g 18. Ln-8i SMx8i+ 19. +DK-5h mate
D27 - Mate in 13: 1. +RCx12k Lnx12k 2. +Bx12k Kx12k 3. +Rx11k Kyx11k+ 4. L-12d+ SMx12d (4... K-11l 5. +VMx11k Kx11k 6. +VM-11i mate) 5. +VM-12h Ln-12j 6. +VMx12j Kx12j 7. +VM-12l K-11i 8. +B-8l +P-9k 9. +Bx9k K-10i 10. +B-10j K-9h 11. +B-8h K-10i 12. +B-9i K-11j 13. +B-10j mate
D28 - Impossible and weird Forsyth has BT, diagram +BT
D31 - With promote on entry it is impossible. The intended solution probably is: 1. Ky-12d+ +SMx12d 2. Bx11c+ +VMx11c (2... Cx11c 3. +SMx3b VMx3b 4. DHx3b+ +Lx3b 5. Phx12a+ Rx12a 6. RCx12a+ mate or 2... +Lx11c 3. +SMx3b VMx3b 4. DHx3b+ +Lx3b 5. +SMx10a Kyx10a 6. Ph-10b= K-12a 7. Phx10a+ +L-11a 8. +DK-10c mate) 3. +SMx3b +Lx3b 4. Phx12a+ Rx12a 5. DH-7f +Lx7f 6. +SMx2b K-11a 7. +SM-3a K-11b 8. +SM-4b K-11a 9. +SM-5a K-11b 10. +SM-6b K-11a 11. +SM-7a K-11b 12. +SM-8b K-11a 13. +SM-9c K-11b 14. +DK-10c (14. +SM-10c? K-10b 15. +SM-11d +L-10i!) Kx12c 15. +DK-10e K-11b 16. +SM-10c K-10b 17. +SM-11d K-9a 18. +DK-9f K-8b 19. +SM-9b K-9a 20. +SMx12b +VM-9e 21. +DKx9e K-8a 22. +DK-9b K-7a 23. +DK-7b mate But this is refuted by 3... VMx3b, after which checking with the DH is not yet possible, and playing Phx12a+ does not force gote to capture back with the Rook, because that Rook is still not threatened by the +SM. So that the Rook can continue to protect the 10-file, and sente's attack fizzles out.
D32 - promoting GB in-zone would be 3 moves faster through 7. GB-4c+, but VM10l and +P10b have no role then. Forsyth has DH in stead of +DH Can be one faster, as 6... K-6b is poor defense (7. FLx6c= Kx6c 8. Lnx9e-8e K-5b 9. Ln-7c K-x4b 10. Ln-5a mate), so that gote should better play Kx5b immediately.
D34 - The solution contains a counter-strike. It does look like the intended solution, though.
D35 - Better defense is 5... +DK-11b 6. +Gx11b K-10c 7. +G-8b K-11c 8. +DK-12d mate. The indicated 6. +DK-12d in this line is not mate at all, as the King can escape to 10c because its own +DK blocked the +RC.
D36 - Faster mate (in 12): 1. +Bx8c Lnx8bx8c 2. P-6b Lnx6b 3. Ky-6c+ Lnx6c-6d (3... Lnx!6c 4. +VM-8c K-5a 5. +BTx6b Bx6b 6. +FL-3c +RCx3c 7. DH-12a+ +SM-7a 8. +DHx7a K-5b 9. +SM-6a K-5a 10. +SMx4c B-7a 11. +DHx7a mate) 4. +BTx6d +SMx6d 5. DH-6c+ K-5a 6. +FL-3c +RCx3c 7. R-1a+ +RCx1a 8. +L-1e +RCx1e 9. +FLx1e +Gx1e 10. +VM-3c SMx3c 11. +GB-5a K-5b 12. +DH5b mate
D37 - Impossible. (But interesting line)
D38 - Impossible. After 1. +DH-5f Px5f there is a forced win: 2. Ln-7f Rx7f 3. Ph-4c+ Kx4c 4. +DK-6e K-3c 5. +DK-5e K-2c 6. +DKx4d-3c Kx3c 7. +DHx5c +SMx5c 8. +DKx5c K-2d 9. +DK-1c Kx1c 10. P-1d+ K-1b 11. +P-1c K-2a 12. +P-1b SMx1b 13. SMx1b+ K-1a 14. +SM-3b +VM-1i 15. RCx1i +SM-1h 16. RCx1h mate 1... K-6c refutes the mate, however. This can be repaired by putting a Kylin on 6a.
D39 - Mate in 19 (?) The crux is to block the +FL on 2l with the GB, so you can clean out the four heavy-weight sliders with your Lions on 10d, leaving the Boars a free field to finish the job. HaChu cannot solve this, but gives a promising line, leading to a position it can win: 1. +G-11a Kx11a (1... BTx11a 2. S-11b= Kx11b 3. +SMx9b +DHx9b 4. +RC-11j +SM-11d 5. GB-4j K-10b 6. Lnx9e-10d FKx10d 7. +DHx10d +SMx10d Kyx10d+ mate) 2. S-11b= Kx11b 3. +RC-11j +Cx11j (3... BT-11c 4. +SMx9b +DHx9b 5. Lnx9ex10d FKx10d 6. Kyx10d+ mate or 3... FKx11j 4. Lnx9ex10d +DHx10d 5. Kyx10d+ mate or 3... +SM-11c 4. ) 4. GB-4j +GBx2k 5. Lnx9ex10d +DHx10d 6. Kyx10d+ FKx10d 7. +L-3j +GBx3j This position is a mate in 12: 8. +DHx10d-10c Kx10c 9. +SM-7f K-9c (9... K-10d/11d 10. +SM-4d K-10e 11. +SM-5e K-10d 12. +SM-6d K-10e 13. +SM-8e K-10f 14. +SM-8f K-11g 15. +SM-9g K-11f 16. +SM-9f K-12e 17. +SM-10e K-12f 18. +SM-10h mate) 10. +SM-6f K-8b 11. +SM-5e K-8c 12. +SM7f-6e K-7b 13. +SM-5d K-7a 14. +SM5e-4d K-6a 15. +SM-4c K-5a 16. +SM4d-3c K-4a 17. +SM-2a K-5b 18. +SM-3b K-6a 19. +SM-1a mate Verified after 4. GB-4j:
D40 - Mate in 7 (parasytic?) 1. +FLx4f FKx4f 2. Ln-3i +SMx3i 3. Phx4f K-6g 4. FK-6h K-7f 5. FK-8f K-6g 6. +DK-3d K-5g 7. FK-6h mate
D42 - Impossible. The published solution can be refuted by 8... DE-9i+, as capturing the Crown Prince (9. +RCx9i) releases control over the long diagonal, allowing the King to escape. So sente has to capture the King in stead to satisfy the tsume condition (i.e. keep gote in check), but does not have the power to drive the CP to checkmate.
D45 - The solution assumes in-zone promotion of the BT after 3... K-10a There is no solution under on-entry rules. There is an interesting line, though: 12 -16.21 455281 0:11.75 c12b11 a10b11 d11c11 b11a10 c11a9 a10b11 a9c11 b11c11 e11d10+ c11d10 e8d9+ e9d9 i9d9 d10d9 j2k2 d9d10 j11d11 d10d11 k2d9 d11d12 d9g9 d12e12 f1e2 e12f11 Intended line is probably: 1. +GB-11b Kx11b 2. Ph-10b= K-12c 3. Phx12d= K-11b 4. Ph-10b= Kx10b (4... K-12c 5. +L-12f mate, or 4... K-11a 5. +G-4a +DH-5a 6. +Gx5a Kx10b 7. BT-9a= K-10c 8. R-10b= mate) 5. BTx9c+ Kx9c (5... K-11a 6. +G-4a +DH-8a 7. +Gx8a mate) 6. +DHx9e +DHx9e (6... K-10c 7. BTx9d +DHx9d 8. +DHx9d mate, or 6... K-8c 7. +DHx9d BTx9d 8. FKx9d mate) 7. BTx9d +DHx9d 8. +SM-7c +DH-8c 9. +Lx7e SMx7e but there it runs aground. If the +SM would have been a FK, sente could continue with 10. FKx7e +DH-8d 11. FKx8d K-10c 12. FKx10d mate. But in that case the cute manoeuvre to remove P12d would be lost, because gote cannot afford 2... K-12c due to an immediate 3. FKx13 mate. To preserve that the FK would have to be blocked from reaching 12d, e.g. by a Pawn on 12g. Which again would require relocation of the +L from 7l to 7k in order to discourage 3... Kx2d. But after that the suggested line works. With FK on 12h:
46 - Impossible
D48 - The published solution goes wrong at 5... R-4e, as this line can be refuted with 6... +FLx5e. The correct finish is quite a bit longer (and funnier): 5. +SM-3f Kx3f 6. Ky-3h K-4f 7. R-4e Kx5f 8. Ky-5h K-6f 9. R-6e K-7f 10. Ky-7h K-8f 11. R-8e K-9f 12. Ky-9h K-10f 13. R-10e K-11f 14. Ky-10g K-12f 15. R-12e SMx12e 16. +Gx12e Kx12e 17. Ky-10e K-12f 18. Ky-11d+ K-12g 19. +Ky-10e K-11h 20. +Kyx9g K-12h 21. +Ky-10i mate
D49 - Mate in 7: 1. FL-6d= Kx8b (1... K-7d 2. FLx7e +Lx7e 3. +VMx7d K-6e 4. +Gx5f SMx5f 5. +B-8g +BT-7f 6. +BT-6k SM-6f 7. +Bx7f mate or 1... K-8d 2. FLx7e= K-9c 3. FLx11e+ Gx11e 4. +GBx10b BTx10b 5. +VMx11e K-10c 6. +B-10d mate) 2. FLx11e+ G-10d (or 2... Gx11e same, or 2... K-9a 3. +DK-7c +RCx7c 4. FLx7c+ R-8b 5. +FL11ex8b BTx8b 6. +GBx10b mate) 3. +Bx10d +Lx10d 4. +VM-9c Kx9c 5. FLx7e+ K8b 6. +DK-7a Kx7a 7. +FL-9c mate
D51 - With a SE on 4a in stead of a Falcon: 1. BTx11b+ Kx11b 2. Bx9d+ VMx9d (2... K-11a 3. +B-12a K-10a 4. +FL-9b mate or 2... G-10c 3. +FLx10c K-10b 4. +DK-9a mate) 3. +FL-10c Gx10c (3... Kx10c 4. +DK-8a G-9b 5. +DKx9b K-10d and as from move 8 of main line) 4. RC-12a+ K-10b 5. +RC-10c Kx10c (5... K-11b 6. +DK-10a K-12b 7. +RC-12e B-12d 8. +DH-10b K-12c 9. +RCx12d mate) 6. +DK-10a B-10b 7. +DK-9b K-10d 8. P-11d+ K-9e 9. +DKx9d K-8f 10. +DK-9f K-7e 11. +DKx7f K-6d 12. +DK-6f K-5d (12... K-5c 13. +Lx1g +L-3e 14. +Lx3e K-4b 15. +Lx2d K-3a 16. Lnx3g-2f FK-3k 17. +L-2b K-4b 18. Ln-3e K-4a 19. +FLx5b K-5a 20.Ln6b mate) 13. +FL-7f K-5c (13... Kx4e 14. +L-2g Rx2g 15. Lnx5g-5f mate) 14. +L-g +L-3e (14... R-4d 15. +Lx4d Lnx4d 16. Px4d+ K-4b [16... K-5b 17. +FL-4c K-5a 18. +DK-6a K-4b 19. +DK-5b mate] 17. +DK-6b K-4a 18. +DK-6a K-4b 19. +P-4c mate) 15. Bx3e R-4d 16. Px4d+ FKx4d 17. +DKx4d Lnx4d 18. Bx4d+ K-6c 19. +B-5d K-7d 20. +B-6e K-6c 21. +B-6d K-5b 22. +L-5c K-4a 23. +B-7d C-6c 24. +Bx6c mate After 11 moves:
D52 - Mate in 18: 1. +FL-3g Phx3g (1... +Bx3g 2. P-1f K-1d 3. P-1e Lnx1e 4. Rx2c+ Lnx2c 5. Ky-1f K-1c 6. Ky-2e +FLx1l 7. Kyx2c+ mate) 2. P-1f K-1d 3. P-1e Phx1d (3... Lnx1d 4. Rx2c+ Lnx2c 5. Ky-1f K-1c 6. Ky-2e Ln-1d 7. Kyx3d+ mate) 4. Ky-1f Phx1f 5. Lx15 +B-1e 6. Lx1e Lnx1e 7. Rx2c+ Lnx2c 8. +G-1j B-1h 9. +Gx1h Ln-1e 10. +Gx1e Kx1e 11. G-2f K-2d 12. G-2e K-2c 13. G-2d Kx3b 14. Gx3d+ K-4b 15. BTx5a+ K-5c 16. +RC-5k C-5d 17. +Gx5d K-6c 18. P-6d+ mate
D53 - Impossible
D54 - Flawed: the MSM solution is refuted by 2... DE-8d.
D55 - Solution contains counter-strike against Lion! Otherwise mate in 1! D56 (180) * Mate in 21: 1. P-3d+ +FLx3d (1... Lnx4bx3d 2. +Px3d +FLx3d 3. FKx2d K-3b 4. FK-2b K-4a 5. FK-3a mate) 2. FK-2d Lnx2d 3. Bx2d+ Kx2d 4. +Px3d Kx3d 5. +DH-2e Kx2e 6. +DH-2g K-3d (6... K-3e 7. Ph-4g P-5e 8. +DH-2e mate) 7. +DH-2e Kx2e 8. Ph-4g K-4d 9. +R-2e Kx4c 10. Ph-6e K-4d (10... K-3c 11. +VM-3a SM-3b 12. +VMx3b K-4b [12... Kx3b 13. +Rx2b K-4a 14. Ph-4c+ K-5a 15. +Ph-5b mate] 13. Ph-4c+ K-5b 14. +VM-3c K-6b 15. +R-2b K-7a 16. +Ph-9c K-6a 17. +Ph-8c K-7a 18. +Ph-7b mate or 10... K-3b 11. +R-3c Kx2a/4a 12. +R-3a mate) 11. +R-2d K-4e 12. Ph-4c+ K-5e 13. +Rx5d K-6f 14. +VM-7e Kx7e 15.+R-6e K-8f 16. +R-7f K-9g 17. +R-8g K-10h 18. +R-9h K-11i 19. +R-10i K-12j 20. SM-12k Kx12k 21. +R-12i mate
C1 -
C1 -
Of the 18 problems of the C series that were unsolved in the MSM, HaChu could prove that six have no solution under the known rules. Ten others could be solved, but for one of those the solution seems to be a 'parasitic' one not intended by the composer. For the remaining two problems it depends on the exact promotion rule. Both of those can be solved under the rule where any non-capture that touches the zone (i.e. ends and/or starts inside it) can be a promotion, after a one-turn delay since the deferral. In both these cases the solution does not look like the intended one, however, as some of the attacker's pieces can be deleted without affecting the solution. When non-captures can only promote on entering the zone, however, these problems are proven unsolvable. One of them has a line that looks like the intended solution (by criteria of making essential use of all pieces, as well as elegance), but the line is flawed, as better defense is possible. For the other no such likely intended solution has been identified.
Of the problems 'solved' in the MSM, one problem was found to be flawed.