IQ-Test NR.68

[Paloma]

Has anyone analyzed this study yet?

The first move is given 1.Bf4, then 1...Kd6 ? because 2.a6 is mate in 32
2...fxe5! 3.axb7 (mate 31) Rb8 4.Bxe5 Kxe5 5.Rxd7 a5 6.Kg7

If 1...Rd8 then 2.a6 Rb4 3.Nxd7 (mate 34) e5 4.Nxe5 Kb6 5.a5+ Kxa6 6.Nxc6 (mate 31)
If 1...Rh8 2. Nf7+ e5 3. Bxe5+ fxe5 4. Nxh8 Rb1 5. Nf7 Rg1+ 6. Kf5 Rg2 7. Nxe5 Rf2+ 8. Kg6 Kd6 9. Re8 Ra2 10. Nf7+

[pgn][Event "Sting IQ-Test"]
[Site "?"]
[Date "2017.08.13"]
[Round "?"]
[White "Nr.68"]
[Black "?"]
[Result "1-0"]
[Annotator "?"]
[SetUp "1"]
[FEN "2r5/prkpR1p1/2p1ppK1/P1p1N1B1/P1P1P3/8/8/8 w - - 0 1"]
[PlyCount "17"]

1. Bf4 $1 {38295 in HHdbVI Bondarenko & Kuznetsov} Kd6 $2 (1... Rh8 {21.46/49} 2. Nf7+ e5 3. Bxe5+ {24.44/31} fxe5 {24.76/30} 4. Nxh8 {24.73/33} Rb1 5. Nf7 Rg1+ {21.24/35} 6. Kf5 Rg2 7. Nxe5 {43.75/41} Rf2+ (7... Rd2 {48.38/38} 8. Kg6 Kd8) 8. Kg6 {49.61/51} Kd6 9. Re8 {43.22/31} Ra2 10. Nf7+)
(1... Rd8 {22.89/49} 2. a6 Rb4 3. Nxd7+ {34#} e5 4. Nxe5+ {33#} Kb6 5. a5+ Kxa6 6. Nxc6 {31#} Ra8 (6... Rxc4 7. Nxd8 Ra4 8. Nb7 Ra3 9. Bd6 Ra2 10. Kxg7 c4 11. Kxf6) 7. Nxb4+ cxb4 $1 8. Be3 {29#} b3 $1 9. Re6+ Kb7 10. a6+ {27#} Kc7 $1 11. Re7+ Kd6 12. Rb7 {25#} Ke5 13. Rxb3 Kxe4 14. Bg1 {23#})
2. a6 $1 {32#} Rbc7 $2 (2... fxe5 $1 3. axb7 {31#} Rb8 4. Bxe5+ Kxe5 5. Rxd7 a5 6. Kxg7 Re8 7. Kf7 Rh8 8. Re7 Rb8 9. Rxe6+ Kd4 10. Re7 Kxc4 11. e5 Kb3 12. Rd7 c4 13. e6 c3 14. e7 c2 15. e8=Q Rxe8 16. Kxe8 c1=Q 17. b8=Q+ Kc4) 3. Rf7 $1 {28#} (3. Rxg7 $4 fxe5 4. Bg5 Re8 {draw}) 3... fxe5 $1 4. Bg5 $1 {27#} Rb7 $1 5. axb7 {26#} Rb8 $1 6. Be7+ {25#} Kc7 7. Rf8 Rxf8 8. Bxf8 Kxb7 9. Bxc5 {22#} 1-0[/pgn]

[peter]

Has anyone analyzed this study yet?

What exactly is your question? Why 2...Kd6 is given as aúthor's main solution?
Answer to that would simply be, because he (they) thought it to be the thematically most interesting one probably. Of course that doesn't mean, it's the one with longest DTM, because that's not a mate in x- puzzle.

After some Forward- Backward with SF 16 (to be able to let it ponder without NNUE) and 6men Syzygys gives this one output in MultiPV=6 in depth 36:

Code: Select all

2r5/prkpR1p1/2p1ppK1/P1p1N3/P1P1PB2/8/8/8 b - - 0 1

Analysis by Stockfish 16:

1. +- (7.03):  1...Th8 2.Sf7+ e5 3.Lxe5+ fxe5 4.Sxh8 Tb2 5.Sf7 Tg2+ 6.Kf5 Ta2 7.Sxe5 Tf2+ 8.Kg6 Kd6 9.Te8 Tg2+ 10.Kf7 g5 11.Te7 Th2 12.Sg6 Kc7 13.Ke8 Kb7 14.e5 Ka6 15.Kxd7 Kxa5 16.e6 Kb4 17.Se5 Td2+ 18.Kxc6 Te2 19.Tb7+ Kc3 20.Kd6 Td2+ 21.Kxc5 Te2 22.Kd5 Td2+ 23.Kc6 Te2 24.Tb5 Th2 25.e7 Th8 26.c5 a6 27.Tb6 Kd4 28.Kd6 Th6+ 29.Kd7 Th8 30.Sf7 Tg8 31.c6 g4

2. +- (28.42):  1...Ta8 2.Txg7 Td8 3.Kxf6 Kc8 4.a6 Tb6 5.Sf7 Tf8 6.Ke7 Txa6 7.Sd6+ Kc7 8.Kxf8 Txa4 9.Ke8 a6 10.Txd7+ Kb6 11.Ke7 Ka5 12.e5 Kb4 13.Kxe6 Ta1 14.Kf6 Tf1 15.Kf5 Te1 16.e6 a5 17.Ta7 Kb3

3. +- (31.12):  1...Kd6 2.a6 Tbc7 3.Tf7 fxe5 4.Lg5 Tb7 5.axb7 Tb8 6.Le7+ Kc7 7.a5 Txb7 8.Lxc5 Tb3 9.Lxa7 Tg3+ 10.Kh7 Td3 11.Lb6+ Kb7 12.Kxg7 Ka6 13.Kf6 Tf3+ 14.Ke7 Tc3 15.Kd6 Txc4 16.Txd7 Kb5 17.Kxe5 Tc1 18.Kxe6 Tc4 19.Ke5 Tc2 20.Kd6

4. +- (31.18):  1...Tg8 2.a6 Tb3 3.Sxd7+ e5 4.Sxe5+ Kb6 5.Sd7+ Ka5 6.Sxc5 Tb2 7.Txa7 Tg2+ 8.Kf7 g5 9.Ld6 Th8 10.Tb7 Th7+ 11.Ke6 Td2 12.Txh7 Kb4 13.Tb7+ Kxc4 14.a7 Kd4 15.Kxf6 Ke3 16.Kxg5 Kf2 17.e5 Kg1 18.Kf5 Tf2+ 19.Ke6 Te2 20.Kd7 Tf2 21.e6 Tf1

5. +- (31.28):  1...Td8 2.a6 Tb2 3.Sxd7+ e5 4.Sxe5+ Kb6 5.Tb7+ Kxa6 6.Txb2 fxe5 7.Lxe5 Te8 8.Kf5 Tf8+ 9.Ke6 Te8+ 10.Kd6 g6 11.Tb1 g5 12.Tg1 Tg8 13.Kxc6 g4 14.Ld6 Tc8+ 15.Kd5 Tg8 16.e5 Kb7 17.Tb1+ Ka8 18.e6 g3 19.e7 Te8 20.Lxc5 a6 21.Tb2 Tc8

6. +- (31.28):  1...Kd8 2.Txg7 fxe5 3.Lxe5 Tb1 4.Tg8+ Ke7 5.Lf6+ Kd6 6.Txc8 e5 7.Te8 Tg1+ 8.Kf7 Tf1 9.Txe5 Th1 10.Te8 Kc7 11.Te7 Kb7 12.Txd7+ Ka6 13.e5 Th7+ 14.Ke6 Th6 15.Kd6 Kxa5 16.Tb7 Ka6 17.Kxc6 Tg6 18.Tb3 Tg8 19.Tb1 Tc8+ 20.Kd7 Tf8 21.Tb3

And after reducing the output- lines to MultiPV=1 and giving in 1...Rh8 (which you seem to think best defend for Black too?):

[d]7r/prkpR1p1/2p1ppK1/P1p1N3/P1P1PB2/8/8/8 w - - 0 1

Analysis by Stockfish 16:

2.Sf7+ e5 3.Lxe5+ fxe5 4.Sxh8 Tb2 5.Sf7 Tg2+ 6.Kf5 Ta2 7.Sxe5 Tf2+ 8.Kg6 Kd6 9.Te8 Kc7 10.Ta8 Tf6+ 11.Kg5 a6 12.Ta7+ Kd6 13.Sxd7 Th6 14.Sb6 Th1 15.Kg6 Ke6 16.Kxg7 Tg1+ 17.Kf8 Th1 18.Te7+ Kf6 19.Ke8 Te1 20.e5+ Kf5 21.Kd7 Ke4 22.e6 Kd4 23.Kd6 Kc3 24.Ta7 Kb4 25.Txa6 Td1+ 26.Kxc6 Te1 27.e7 Th1 28.Kd7 Tf1 29.Ta8 Kb3 30.a6
Tiefe: 37/68 00:09:12 33326MN, tb=81984212
+- (15.77)

So, all the 6 moves in output after 1.Bf4 show clearly winning eval and output- lines, as far as I see in your .pgn, you come to the mainly same conclusion, don't you?
Regards

[Paloma]

It doesn't matter if it's a study or a mate in-x, it's fun to trace the moves back to the root to see if it's the best one.
It seems that the 1st move is not the only winning move.
Finding out if one of the best moves is the best move at all or even leads to mate is what makes an analysis so appealing, isn't it?

[peter]

It seems that the 1st move is not the only winning move.

But?
Which other one first move besides 1.Bf4 is winning too?

[Eelco de Groot]

I think it was stated in general by Herbert, not just this specific study. One of many builds by Eduard I downloaded a while ago, it finds the key move quickly. This PV with ...Rh8 No other winning moves in sight


[d]2r5/prkpR1p1/2p1ppK1/P1p1N1B1/P1P1P3/8/8/8 w - -

Engine: PROMENADE 4 threads (1024 MB)
gemaakt door Stockfish authors and E. Nemeth

57 41:52 +6.53 1.Lf4 Th8 2.a6 Tb1 3.Pxd7+ Kd8 4.Kf7 g5
5.Ld6 Th7+ 6.Kxe6 Txe7+ 7.Lxe7+ Kc8
8.Pxf6 Tb4 9.e5 Txc4 10.Kf5 Tf4+
11.Kg6 Txa4 12.e6 Txa6 13.Ld6 Ta3
14.Le5 (5.489.215.036) 2184

57 41:52 0.00 1.a6 Tb4 2.Pxd7 fxg5 3.Kf7 Td8
4.Kxe6 Txd7 5.Txd7+ Kb6 6.Tb7+ Kxa6
7.Txg7 Txc4 8.e5 Txa4 9.Kd6 Kb6
10.e6 Td4+ 11.Ke5 Td1 12.Txg5 c4
13.e7 c3 14.Ke6 (5.489.215.036) 2184

57 41:52 0.00 1.Txd7+ Kb8 2.Lxf6 gxf6 3.Kxf6 Txd7
4.Pxd7+ Kc7 5.Pxc5 e5 6.Kxe5 Th8
7.Ke6 Th6+ 8.Ke7 Th7+ 9.Ke6 Th4 (5.489.215.036) 2184

57 41:52 0.00 1.Lxf6 gxf6 2.Txd7+ Kb8 3.Kxf6 Txd7
4.Pxd7+ Kc7 5.Pxc5 e5 6.Kxe5 Tg8
7.Ke6 Tg4 8.Ke7 Tg7+ 9.Kf6 Tg4 (5.489.215.036) 2184

___________________________________________________________

58 47:11 +6.64 1.Lf4 Kd6 2.a6 Tbc7 3.Tf7 fxe5 4.Lg5 Tb7
5.axb7 Tb8 6.a5 Txb7 7.Le7+ Kc7
8.Lxc5 Tb1 9.Lxa7 Td1 10.Lb6+ Kb7
11.c5 Tg1+ 12.Kh7 g5 13.Txd7+ Ka6
14.Ta7+ (6.165.299.046) 2177

58 47:11 0.00 1.a6 Tb4 2.Pxd7 fxg5 3.Kf7 Td8
4.Kxe6 Txd7 5.Txd7+ Kb6 6.Tb7+ Kxa6
7.Txg7 Txc4 8.e5 Kb6 9.Kf6 Tf4+
10.Kxg5 Txa4 11.e6 Te4 12.Kf5 Te1
13.Tg4 Kc7 14.Tg7+ (6.165.299.046) 2177

58 47:11 0.00 1.Txd7+ Kb8 2.Lxf6 gxf6 3.Kxf6 Th8
4.Kxe6 Th6+ 5.Ke7 Th4 6.a6 Tc7 7.Kd8 Th8+
8.Ke7 Th7+ 9.Kd6 Th6+ 10.Ke7 Kc8
11.Txc7+ Kxc7 12.Pf7 Th4 13.Pd6 Th5
14.Pf7 (6.165.299.046) 2177

58 47:11 0.00 1.Lxf6 gxf6 2.Txd7+ Kb8 3.Kxf6 Th8
4.Kxe6 Th6+ 5.Ke7 Th4 6.a6 Tc7 7.Kd8 Th8+
8.Ke7 (6.165.299.046) 2177

[Dann Corbit]

Here is my database record for that position:
[d]2r5/prkpR1p1/2p1ppK1/P1p1N1B1/P1P1P3/8/8/8 w - - acd 69; bm Bf4; ce 626; c0 "2.hm Tidskrift for Schack#2235; 1982; Bondarenko=F Kuznetsov=AP; (+0711.47g6c7); 1-0"; c1 "Bf4, 27"; c3 "Bf4"; c4 "Bondarenko, &Kuznezov_Glarean, PoorStockfish_HTC108-29, 163"; c5 "Bondarenko=F Kuznetsov=AP; 1-0"; c6 "Bondarenko, &Kuznezov_Glarean, PoorStockfish_HTC108-29, 13"; c7 "2.hm Tidskrift for Schack#2235;1982;W:Bondarenko=F Kuznetsov=AP;(+0711.47g6c7);1-0;1982"; c8 "pv Bf4 Kd6 a6 Rbc7 Rf7 fxe5 Bg5 Re8 Be7+ Rxe7 Rf8 Rf7 Kxf7 g5 Rb8 g4 Ke8 g3 Kd8 g2 Rb1 1-0"; c9 "HHdbVI.0794086.001a.38134"; pm Bf4; pv Bf4 Kd6 a6 Rbc7 Rf7 fxe5 Bg5 Rb7 axb7 Rb8 a5 Rxb7 Be7+ Kc7 Bxc5 Rb1 Bxa7 Rd1 Bb6+ Kb7 Kxg7 c5 Bxc5 Rc1 Bb6 Rxc4 Rxd7+ Ka6 Kf6 Rxe4 Kxe6 Re2 Rc7 Kb5 Kd5 e4;