A. Background
I have encountered this puzzle (black to move) today and failed to solved it after two successive correct moves ( 27...Qh3+ 28.Kg1 Qxg3+ ) because this puzzle takes more than two moves to solve and my third move (29...Re1+) did not match the solution move but it was a good move, a comment pops up "Good move, but you can do better". I was given a chance to make a new move because my 1st third move is good, and after executing my 2nd third move (29...Qe3+) the puzzle was not solved. My training rating change for this puzzle is -29.
B. Puzzle Profile
Puzzle no.: 55798
Puzzle Link: http://en.lichess.org/training/55798
FEN: 2r1r1k1/p4p1p/5Qpq/3P2n1/3P4/2N3P1/PBPR2K1/R7 b - - 1 27
Game Link: http://en.lichess.org/bvk3ccju/black#53
Goal: Find the best move for black
Solution: 27...Qh3+ 28.Kg1 Qxg3+ 29.Rg2 Nf3+ ( 29...Re1+ { Good move, but you can do better } ) 30.Qxf3 Qxf3 *
C. Puzzle analysis
Done basic analysis of this puzzle comparing
a) 29...Nf3 (the solution)
b) 29...Re1 (the good, my first attempt move)
c) 29...Qe3 (failed, my second attempt move)
Run the engine at multipv 3.
Position after 29.Rg2
2r1r1k1/p4p1p/5Qp1/3P2n1/3P4/2N3q1/PBP3R1/R5K1 b - - 0 29
Analysis by Stockfish 180116 64 POPCNT:
1. -+ (-#25): 29...Re1+ 30.Rxe1 Qxe1+ 31.Kh2 Qh4+ 32.Kg1 Nh3+ 33.Kh2 Qxf6 34.Kxh3 Re8 35.Bc1 Qf3+ 36.Kh2 Re1 37.Ne2 Rxe2 38.Rxe2 Qxe2+ 39.Kg3 Qe1+ 40.Kf3 Qxc1 41.d6 Qxc2 42.Ke3 Qxa2 43.Ke4 Qe6+ 44.Kd3 Qxd6 45.Ke4 Qe6+ 46.Kd3 h5 47.Kc3 h4 48.d5 Qxd5 49.Kb2 h3
2. -+ (-13.11): 29...Nf3+ 30.Qxf3 Qxf3 31.Rf1 Qe3+ 32.Kh2 Rxc3 33.Bxc3 Qxc3 34.Rff2 Qxd4 35.Re2 Rxe2 36.Rxe2 Qxd5 37.Kg3 Qxa2 38.Rf2 h5 39.Kh2 Qc4 40.Rg2 Qf4+ 41.Kh1 Qc1+ 42.Kh2 Qe1 43.Kh3 Qe5 44.Rf2 Qe3+ 45.Kg2 Kg7 46.Kf1 Qd4 47.Kg2 Qd5+ 48.Kh3 Qg5 49.Kh2 Qe5+ 50.Kg1 Qc5 51.Kg2 Qc6+ 52.Kf1 Qc4+ 53.Ke1
3. -+ (-2.46): 29...Qe3+ 30.Rf2 Nh3+ 31.Kg2 Nxf2 32.Qxf2 Rxc3 33.Bxc3 Qxc3 34.Rf1 f5 35.Rd1 Qc4 36.Re1 Rxe1 37.Qxe1 Qxd5+ 38.Kg3 Qxd4 39.Qe6+ Kg7 40.c4 Qc5 41.Qd7+ Kh6 42.Kg2 Qxc4 43.Qxa7 Qe2+ 44.Kg1 g5 45.a4 g4 46.Qb6+ Kh5 47.Qc7 Qe3+ 48.Kg2 Qe4+ 49.Kf2 Qd4+ 50.Kf1 h6 51.a5 Kg5 52.Qe7+ Kf4 53.Qc7+ Kf3 54.Qc6+ Kg3 55.Ke2
D. Conclusion
The multipv analysis in (C) showed that 29...Re1 (the good) is better than 29...Nf3 (the solution).
My 2nd attempt move 29...Qe3 had failed, though it is winning had received a big -29 rating points deduction.
It is possible that the evaluation of 29...Nf3 could be higher but probably does not exceed to that of 29...Re1.
Perhaps this puzzle has to be retired.
I have encountered this puzzle (black to move) today and failed to solved it after two successive correct moves ( 27...Qh3+ 28.Kg1 Qxg3+ ) because this puzzle takes more than two moves to solve and my third move (29...Re1+) did not match the solution move but it was a good move, a comment pops up "Good move, but you can do better". I was given a chance to make a new move because my 1st third move is good, and after executing my 2nd third move (29...Qe3+) the puzzle was not solved. My training rating change for this puzzle is -29.
B. Puzzle Profile
Puzzle no.: 55798
Puzzle Link: http://en.lichess.org/training/55798
FEN: 2r1r1k1/p4p1p/5Qpq/3P2n1/3P4/2N3P1/PBPR2K1/R7 b - - 1 27
Game Link: http://en.lichess.org/bvk3ccju/black#53
Goal: Find the best move for black
Solution: 27...Qh3+ 28.Kg1 Qxg3+ 29.Rg2 Nf3+ ( 29...Re1+ { Good move, but you can do better } ) 30.Qxf3 Qxf3 *
C. Puzzle analysis
Done basic analysis of this puzzle comparing
a) 29...Nf3 (the solution)
b) 29...Re1 (the good, my first attempt move)
c) 29...Qe3 (failed, my second attempt move)
Run the engine at multipv 3.
Position after 29.Rg2
2r1r1k1/p4p1p/5Qp1/3P2n1/3P4/2N3q1/PBP3R1/R5K1 b - - 0 29
Analysis by Stockfish 180116 64 POPCNT:
1. -+ (-#25): 29...Re1+ 30.Rxe1 Qxe1+ 31.Kh2 Qh4+ 32.Kg1 Nh3+ 33.Kh2 Qxf6 34.Kxh3 Re8 35.Bc1 Qf3+ 36.Kh2 Re1 37.Ne2 Rxe2 38.Rxe2 Qxe2+ 39.Kg3 Qe1+ 40.Kf3 Qxc1 41.d6 Qxc2 42.Ke3 Qxa2 43.Ke4 Qe6+ 44.Kd3 Qxd6 45.Ke4 Qe6+ 46.Kd3 h5 47.Kc3 h4 48.d5 Qxd5 49.Kb2 h3
2. -+ (-13.11): 29...Nf3+ 30.Qxf3 Qxf3 31.Rf1 Qe3+ 32.Kh2 Rxc3 33.Bxc3 Qxc3 34.Rff2 Qxd4 35.Re2 Rxe2 36.Rxe2 Qxd5 37.Kg3 Qxa2 38.Rf2 h5 39.Kh2 Qc4 40.Rg2 Qf4+ 41.Kh1 Qc1+ 42.Kh2 Qe1 43.Kh3 Qe5 44.Rf2 Qe3+ 45.Kg2 Kg7 46.Kf1 Qd4 47.Kg2 Qd5+ 48.Kh3 Qg5 49.Kh2 Qe5+ 50.Kg1 Qc5 51.Kg2 Qc6+ 52.Kf1 Qc4+ 53.Ke1
3. -+ (-2.46): 29...Qe3+ 30.Rf2 Nh3+ 31.Kg2 Nxf2 32.Qxf2 Rxc3 33.Bxc3 Qxc3 34.Rf1 f5 35.Rd1 Qc4 36.Re1 Rxe1 37.Qxe1 Qxd5+ 38.Kg3 Qxd4 39.Qe6+ Kg7 40.c4 Qc5 41.Qd7+ Kh6 42.Kg2 Qxc4 43.Qxa7 Qe2+ 44.Kg1 g5 45.a4 g4 46.Qb6+ Kh5 47.Qc7 Qe3+ 48.Kg2 Qe4+ 49.Kf2 Qd4+ 50.Kf1 h6 51.a5 Kg5 52.Qe7+ Kf4 53.Qc7+ Kf3 54.Qc6+ Kg3 55.Ke2
D. Conclusion
The multipv analysis in (C) showed that 29...Re1 (the good) is better than 29...Nf3 (the solution).
My 2nd attempt move 29...Qe3 had failed, though it is winning had received a big -29 rating points deduction.
It is possible that the evaluation of 29...Nf3 could be higher but probably does not exceed to that of 29...Re1.
Perhaps this puzzle has to be retired.