January statistics

Games: 13

White: 6

Black: 7

Won: 10

Drawn: 2

Lost: 1

Shortest game: 17 moves (won)

Longest game: 105 moves (drawn)

Rating at the start of the month: 1631

Rating at the end of the month: 1695

Minimum/maximum rating: 1631/1695

Short, sweet and simple

String Quartets (Brazil) - Hennie Schaper

King's Indian Defence

1. c4 Nf6 2. g3 g6 3. Bg2 Bg7 4. e4 d6 5. d4 0-0 6. Nc3 c6 7. Nge2 e5 8. 0-0 Nbd7 9. Re1 Re8 10. Bg5 h6

So far it has been a reasonably normal sequence of moves for this opening. White's next move is not a real mistake, but conceding the bishop's pair in a position that can be ripped open any time may not be the best idea either.

11. Bxf6 Nxf6 12. dxe5 dxe5 13. Qxd8 Rxd8 14. Rad1 Be6 15. b3 Kf8 16. f4

This is a real mistake though. Black's knight can now exploit the weakness of square e3. A move like Nc1 would have been better.

16. ... Ng4 17. Nc1 

Tempting but wrong. After Rxd8 black is a bit better but white still has plenty to play for.

17. ... exf4 18. gxf4 Bxc3

And black is a piece up with all kinds of additional threads. To my surprise white offered a draw, but before I could answer, he resigned. Later I found out that this was his first game on the site, so I ascribe it to hitting the wrong button. He was clearly no chess newbie given the solid opening play - and the start ranking of 1600 assigned by the site.

0-1.

The Seesaw Sea Snake

UmarXudayberdiyev (Uzbekistan) - Hennie Schaper

King's Indian Defence

1. c4 Nf6 2. d4 d6 3. h3 g6 4. e3 Bg7 5. Bd3 0-0 6. g4 e5 7. Nf3

White has played an unorthodox but fairly aggressive attack against the King's Indian. This move is marked as a mistake though in the post-game analysis. I did see the fork option with e4, but did not think black would come out better after g5. The computer disagrees, giving the line 8. ... exd3 9. gxf6 Qxf6 10. Nc3 Re8 11. e4 Nc6 as clearly better for black.

7. ... exd4 8. Nxd4 Re8 9. Ne2 Nc6 10. Bd2

Time for a blunder. Tempting but wrong to play Nxg4 with a small material gain (rook and two pawns for bishop and knight), but leaving white with far more play than necessary. Instead d5 would give black a very nice game.

10. ... Nxg4 11. hxg4 Bxb2 12. Nbc3 Nxa1 13. Qxa1 Ne5 14. Be4 Bxg4 15. Nf4

Time for another blunder. I should have consolidated with c6. Instead I forced white to give up the bishops pair, but the black knight is more useful than the white bishop in this position. The computer rates the position after my next move is roughly equal.

15. ... Nf3+ 16. Bxf3 Bxf3 17. Rh2 Qf6 18. Nfe2 Bxe2 19. Kxe2 Re7

Blunder number three. I did realize that this puts Nd5 as a killing option in the position, but disregarded it because at the moment the knight is pinned because of the unprotected queen on a1. What I did not see is how easy white can unpin with a threat.

20. Qh1 h5 21. Nd5 

Now, after the most sensible move Qe6 white takes the rook and has about equal material with bishop versus three pawns, but all the play. I decided to mix things up - and white got greedy. 

21. ... Qg5 22. e4 Qg4+ 23. f3 Rxe4+ 24. Be3 (the simple Kd1 wins) Rxe3+ 25. Nxe3 Qe6 26. Qg1 Re8

The gamble paid off - black has four pawns for the knight, a good pawn structure and active play.

27. Kd2 Kf8 (better would have been Qe5) 28. Re2 (better: Nd5) Qf6 29. Qb1 Qd4+ 30. Qd3

Time for blunder number four. Black needs to keep the queens on the board to better utilize the army of pawns. Qf4 and keeping on advancing the h-pawn is probably winning for black.

30. ... Qxd3 31. Kxd3 c6 32. Rb2 b6 33. a4 Kg7 34. Ra2 Re5 35. f4 Re7 36. a5 Kf6 37. abx6 axb6 38. Nc2

Blunder number five, and even worse, this is really a missed win. With Kf5 followed by Kxf4 (after e.g. Nd4+) white is losing. I did not see it. In the coming moves black cannot hold on to his extra pawns.

38. ... h4 39. Nd4 Rc7 40. Rh2 g5 41. fxg5+ Kxg5 42. Nf3+ Kg4 43. Nxh4 f5 44. Ng6 b5 45. Rc2 bxc4+ 46. Rxc4+ Kg5 47. Nf5 Rc8 48. Ne6+ Kf6 49. Nd4 d5 50. Rc5 f4 51. Nxc6+ Rc7 52. Kd4 Kg5 53. Rxd5+ Kg4 54. Ne5+ Kg3 55. Ke4 Ra7 56. Rd3+ Kf2 57. Kxf4

This is a drawn end game provided black plays it right (keep the king from the rims, and do not fall for knight forks or rook skewers). However, I had less than 5 minutes left and white had 11 minutes. I can't blame him for trying. I will not list the rest of the moves - white continued to probe, black did not blunder again, and on move 81 white actually lost the knight by carelessness. However, at that point white still had six minutes on the clock and I was down to two and a half. Probably the KR versus KR end game would be considered as a win for white when time runs out for black (black can be stupid and lose this), so white kept playing - but I did not blunder any more. At move 105 (in Dutch a chess game of over 100 moves is called a zeeslang, or sea serpent) I could claim a draw for three times the same position (with almost 2 minutes left). 1/2 - 1/2

In the end, given all my blunders I was happy with the draw against a higher rated opponent. I was particularly glad that I played the end games KRN-KR and KR-KR well at top speed.

Mindgames

ammar8013 (Iraq) - Hennie Schaper

Alekhine Defence

1. e4 Nf6 2. e5 Nd5 3. d4 d6 4. c4 Nb6 5. Nf3 Bg4 6. Nbd2 e6 7. Be2 Be7 8. h3 Bh5 9. Qb3

The first eight moves were pretty normal for the Alekhine. White now puts pressure on the queen side, in particular on the weak square b7. I have had similar positions in training matches against various levels of computer programmes at chess.com, and always struggled to equalize. Here I choose the wrong continuation: dxe5 was best. 

9. ... c5 10. exd6 Bxd6 11. dxc5 Bxc5 12. Ne4 Qc7 13. Nxc6 Qxc5 14. Be3 Qa5+ 15. Bd2 Qa4 16. Qd3 0-0 17. 0-0 Bg6 18. Qc3 Qc2 19. Qxc2 Bxc2 20. Rac1 Bg6 21. c5 Nd5 22. Ne5 Nc6 23. Nxg6 hxg6 24. a3 a5 25. Bb5

White has all the play: the bishops pair, the better pawn structure, queenside majority and more active pieces. But black has knights and sometimes opponents do not see where they are going. Like here.

25. ... Nd4 (please play Ba4, please play Ba4....) 26. Ba4 Ne2+

And suddenly black is an exchange up. There is still some work to do to cash in on the advantage though.

27. Kh1 Nxc1 28. Rxc1 Rfd8 29. Bg5 f6 30. Bh4 Nf4 31. Bd1 Rd2 32. b4 axb4 33. axb4

Black has made tremendous progress after winning the exchange. The main concern is the potential creation of a passed white pawn on the c-file. But first the remaining knight does more damage.

33. ... Nd3 34. Rb1 Nxf2+ 35. Bxf2 Rxf2 36. Bf3 Rb8 37. Kh2 f5 38. Kg3 Rc2 39. Kf4 Kf7 40. Ke5 Ke7 41. g4 Rc3 42. Bg2 Rg3 43. Rb2 fxg4 44. hxg4 Rxg4

Black has of course a completely won position by now. I still had 7 minutes for the rest of the game and white could have spared himself the remaining 25 moves (should have been less, but I was less focused).

45. Bh3 Rg3 46. Bg2 g5 47. c6 bxc6 48. Bxc6 Rg1 49. b5 Rc1 50. Rd2 Re1+ 51. Kd4 Rd8+ 52. Kc3 Rxd2 53. Kxd2 Rb1 54. Kc2 Ra1 55. Kb3 Kd6 56. Kc4 g4 57. Kd3 g3 58. Ke3 Ra3+ 59. Ke2 g2 60. Bxg2 Ra2+ 61. Kf3 Rb2 (I had originally planned Rxg2 with a supposedly winning pawn end game, but I suddenly was not sure, so I played it safe) 62. Bf1 Ke5 63. Kg4 Kf6 64. Kf4 Rb4+ 65. Kf3 Kg5 66. Kg3 e5 67. Kf2 Kf4 68. Bd3 e4 69. Bf1 g5 0-1

Poking the Queen

Hennie Schaper  - zarema3884 (Russia)

Sicilian Defence

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e6 6. Bc4 Be7 7. 0-0 a6 8. a4 0-0 9. Bb3 Nbd7 10. Be3 Nc5 11. f3 Nxb3 12. Nxb3 Nd7 13. Nd4

I was not very happy with the way the opening went, but the resulting position is as one would expect from a Sicilian, overall balanced but with plenty of possibilities for both sides. Black's next move is dubious, as white gets to eliminate black's bishops pair, and leave him with the weaker of the two bishops.

13. ... b6 14. Nc6 Qe8 15. Nxe7 Qxe7 16. Qd2 Bb7 17. Rfd1 d5

Tempting but wrong. This is of course a thematic advance for black, and it looks like it's possible in spite of white covering the d5 square more than black, because after exchanges on d5 white's bishop is left unprotected leaving black with the winning Qxe3+. A simple waiting move turns the position into a winning one, as after Bf2 white exploits the fact that the N on d7 is insufficiently protected.

18. Bf2 Rfd8 19. exd5 exd5 20. Nxd5 Bxd5 21. Qxd5 h6 22. Qb7 Qe6 23. Qd5 Qe7 24. Re1 Qf6

From a material point of view, black is only one pawn done, but white has all the play: strong bishop versus knight, pawn majority on the queen side, and active pieces all around. White can now poke the black queen, as a queen exchange would only increase the values of his strong points.

25. Bd4 Qg6 26. Qe4 f5 27. Qd5+ Kh7 28. Re6 Qg5 29. Be3

Now black blunders, giving away a knight, probably only looking at the line 30. Bxg5 Rxd5. A knight down as well, black is completely lost, plays a few more moves and resigns literally one second before I can play a nice mate in one with the rook.

29. ... Ne5 30. Qxe5 f4 31. Bxf4 Qxe5 32. Bxe5 Rd2 33. Re7 Rg8 34. Rc1 Kg6 35. Bc3 Rdd8 36. Re6+ Kf5 37. Rxb6 g5 1-0

A comedy of errors

Slmz0707 (Turkey) - Hennie Schaper

Noa Gambit

1. e4 Nf6 2. Nc3 e5 3. Nf3 Nc6 4. Bc4 Nxe4 5. Bxf7+ Kxf7 6. Nxe4 d5 7. Nc3 e4 8. Ng1

Via a declined Alekhine defence the game transposed into the Noa gambit, a variation of the Italian Four Knights Game. Unlike most gambits, white does not give up material but positional aspects for an attack. It is probably better for black. My next move is a mistake though (Bf5 would have been better), but white does not respond adequately and I managed to strengthen my position.

8. ... Qg5 9. g3 Bg4 10. f3 exf3 11. Nxf3 Re8+ 12. Kf2 Bc5+

Tempting, but wrong. White took quite some time for his reply, and during that time I saw that 13. d4 leads to a fairly equal game. My mistake in planning Bc5 was that I thought I could always play Bxf3 in-between - not realizing that the recapture Qxf3 is check and disrupts my ideas. Fortunately, white played an inferior move now - once more failing to capitalize on my error.

13. Kg2 Qh5

Threatens a cute two bishops mate on h3, while increasing the pressure on the knight...

14. h4 Rhf8 15. Rf1 Kg8 16. d3 Nd4

White is lost, the pin loses material. The remaining moves don't matter too much - in addition to the material advantage (enhanced by white blundering a knight at move 23), black has all the play.

17. Bf4 Bxf3+ 18. Rxf3 Qxf3+ 19. Qxf3 Nxf3 20. Kxf3 c6 21. a3 h6 22. b4 Bd4 23. Kg2 Bxc3 24. Rc1 Re2+ 25. Kh3 h5 26. d4 Bb2 27. Rb1 Bxa3 28. c3 Bb2 0-1 

Needles and pins

ktji (UK) - Hennie Schaper 

Vienna Game

1. e4 Nf6 2. Nc3 e5 3. d4 exd4 4. Qxd4 Nc6 5. Qd1 Bc5 6. h3 d6 7. Nf3 Qe7 8. Bd3 Bd7 9. 0-0 0-0-0

The opening has gone well for black. White refused the Alekhine's defence and transposed into the Vienna game, but wasted some time with the Queen moves, and weakened the king side with the pawn move to h3. The scene is set for a sharp game with opposite castling.

10. Bg5 h6 11. Nd5 Qe6 12. Nxf6 gxf6 13. Bh4 Rhg8 14. Bg3

White is already lost after some inaccuracies and the blunder Bg3. The pins are killing - and quickly.

14. ... Rxg3 15.b4 Qxh3 16. Nh4 

16. ... Rxg2+ 17. Nxg2 Rg8 0-1

It's mate in two. One of my quickest wins since I started playing chess again.

The last thing on my mind

qwert9888 (Russia) - Hennie Schaper

Leonardis Opening

1. e4 Nf6 2. d3 e5 3. Nf3 Nc6 4. Nc3 Bb4 5. Bd2 0-0 6. a3 Bxc3 7. Bxc3 d6 8. h3 Qe7 9. Be2 Nd8 10. 0-0 Ne6 11. Bd2 Bd7 12. c3 a5 13. Qc2 Bc6 14. Ng5 h6 15. Nxe6 Qxe6 16. f4

After the somewhat supersafe way of dodging the Alekhine defence, white has played the opening better than black, getting his pieces ready for a king side attack. I was not comfortable at all with this position, and that may have influenced my thinking later on.

16. ... exf4 17. Bxf4 Rfe8 18. Bf3 Qd7 19. Rae1 Re7 20. Qd1 Rae8 21. Bg3 Re6 22. Bh4 

White still has the better position, but did not make much progress. Black's position still looks defendable, but my next move weakens the position. Of course I had to deal with the threat Bxf6 followed by Bg4, but there were better ways to do that.

22. ... g5 23. Bg3 Qe7 24. h4 Nh7 25. Bg4 Rf6 26. Bf5 Qd8 27. e5 dxe5 28. Bxh7+ Kxh7 29. hxg5

By now I was convinced I was going to lose this game, based on my dislike of the position, the fact that my opponent had a higher rating, and that I was down to 8 minutes for the rest of the game while white still had 23 minutes left. The last thing on my mind was looking for a winning move. Unfortunately, because after white's last move (a mistake) I could have gotten a winning position. I should have played Rxf1, followed by Qxg5, pinning the black bishop on g3 with loads of threats. Instead, I went down quickly:

29. ... Qd5 30. Qe2 Rxf1 31. Rxf1 Rg8 32. c4 Qe6 33. Rf6 1-0

Third row rooks

Hennie Schaper - 1Jack2 (Netherlands)

Sicilian defence

1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nxc6

Not the most common move in this position, but I've had problems with complications arising from other moves in this line - so a simplifying move that is still sound appealed to me.

5. ... bxc6 6. Bd3 g6 7. Be3 Bg7 8. c3 Ne7 9. Nd2 d5 10. exd5 cxd5 11. Nf3 0-0 12. Bd4

Aiming to get rid of Black's main defender, the fianchettoed bishop. I was aware from now on that I had to keep being ready to deal with the threat e6-e5-e4 forking the minor pieces.

12. ... Nc6 13. Bxg7 Kxg7 14. 0-0 Qc7 15. Re1 e5 16. Bb5

The computer analysis after the game states that this is the only good move for white. The position is the way I like it, unbalanced with plenty of options.

16. ... e4 17. Bxc6

Objectively Qxd5 is probably better but I did not want to get into the line starting with exf3.

17. ... Qxc6 18. Nd4 Qf6 19. Re3 Ba6 20. Qd2 Bd3 21. Rh3

The attack against the weakened king position starts. The obvious threat that black has to deal with is Qh6+ followed by Qxh7 mate. Possibly h5 is the best way to encounter this, but it does weaken the pawn structure in front of the king further. Black chooses to prepare positioning the queen as surrogate bishop on g7.

21. ... Kh8 22. Re1 a6 23. Re3 Rfe8 24. Reg3 Qg7

25. Nf5

Not difficult to see as an attacking player. My opponent had not seen it I think, and took quite some time for the next move. During that time it occurred to me that e3 could be a good defence for black as white can not ignore the threat e2-e1=Q checkmate. After  25. ... e3 26. Nxe3 white is still winning though.

25. ... Qf8 26. Qg5 Re5 (losing this rook, but worse, white has a forced mate now) 27. Qf6+ Kg8 28. Rxh7 Kxh7 29. Rh3+ Qh6 30. Rxh6+ 1-0

Yes, 30. Qg7 is checkmate one move earlier, but when I see a forced mate, I don't go looking for a quicker one.

The waltz of the black knights

enkhboldking (Mongolia) - Hennie Schaper

Alekhine Defence

1. e4 Nf6 2. e5 Nd5 3. c4 Nb6 4. d4 d6 5. exd6 cxd6 6. Nc3 g6 7. Bd3 Bg7 8. Be3 Nc6 9. Nge2 0-0 10. h4 Nd7

The opening (modern Alekhine, Exchange variation) has resulted in a dynamic confrontation. White has a strong centre, started a king-side attack, but his king is still in the centre. The logical follow-up is white continuing the kingside attack, and white trying to break open the centre.

11. h5 e5 12. d5 Ne7 13. g4 f5

Both attacks are in full swing. The next few moves see white struggle to find a plan, while black continues to improve his position.

 14. g5 f4 15. Bd2 Nc5 16. Bc2 Bf5 17. Ng1 Bxc2 18. Qxc2 Nf5 19. h6 Bh8 20. Nh3

The white attack has been halted for now (h6 was not good), and black is taking over the centre. It is time now for the waltz of the black knights.

20. ... Nd4 21. Qd1 Nd3+ 22. Kf1 Nxb2 23. Qb1 Nxc4 24. Qd3 Nxd2+ 25. Qxd2 Rc8 26. Rc1 Qa5

White resigned. Already two pawns down, further material loss is imminent. 0-1.

In the land of the blind....

Hennie Schaper - joninatadihardja (Indonesia)

Philidor Defence

1. e4 e5 2. Nf3 d6 3. Bc4 Be6 4. Bxe6 fxe6 5. d4 exd4 6. Nxd4 e5

I can't recall ever playing against the old-fashioned Philidor, but that's no excuse for not seeing the simple Ne6 here, with a very nice position for white.

7. ... Nf6 8. Nc3 Be7 9. 0-0 0-0 10. Qe2 Nbd7

There's something about black's weakness on e6 that was a huge blind spot for me in this game. With Ng5 I would have had a second opportunity to exploit it. Still other chances are coming.

11. Rd1 Nc5 12. Ng5

Not bad, and finally hitting at the weak spot, but I did not even see the simple Nxe5. 

12. ... Qe8 13. b4 Na6 15. Ne6 Rf7

Now b5 would be winning for white thanks to the threat on c7. I did not see it. Instead I played the tempting Qc5, which black should have neutralized with Qc6. Fortunately he did not see that one either.

16. Qc5 c6 17. Ng5 d5 18. exd5 Nxd5 19. Nxf7 Qxf7 20. Nxd5 cxd5 21. Qxd5 Nxb4 22. Qxf7+ Kxf7 23. Rd7 Nxc2 24. Rb1 b6

Now that the dust has settled, black looks to still have a fighting chance with a pawn for the exchange. However, the pinned bishop on e7 is a fatal weakness.

25. Bg5 Re8 26. Rc1 Nd4 27. Rcc7 Nf5 28. g4 h6

For a moment it looks like black can get out of the sticky situation, but the bishop simply switches sides.

 

29. Bc1 Nd4 30. Ba3 1-0

Well, I won, against a much higher rated player, but there were too many mistakes along the way...

The bishop bluff

Hennie Schaper - Kimsan15 (Kyrgyzstan)

Ruy Lopez

1. e4 e5 2. Nf3 Nc6 3. Bb5 d6 4. 0-0 Bf6 5. d3 Be7 6. c3 Bd7 7. Qe2 0-0 8. Rd1 Qe8 9. Nbd2 a6 10. Ba4 b5 11. Bc2 h6 12. Nf1 Nh7 13. Ng3 f5

So far it had been pretty straightforward opening play, but black's 13th move is dubious. It sacrifices the bishop's pair and weakens the kingside, where white is already preparing for attack, and gives white chances in the center as well..

14. exf4 Bxf4 15. Nxf4 Rxf4 16. d4 Rf8 17. dxe5 dxe5 18. Nxe5 Nxe5 19. Qxe5 Bd6 20. Qxe8 Raxe8 21. Be3 Ng5 22. Rd4

White is a pawn up and even with the queens off the board, black needs to worry all the time about the king's position given the strength of the bishops.

22. ... Ne6 23. Rg4 Kh8 24. g3 Be7 25. Rd1 Bd6 26. Rd5 Be7 27. Re5 Bd6 28. Rh5 Rf6 29. Bg6 Rd8 

The computer (hindsight analysis) sees this position as a clear win for white, with about a rook's worth of advantage. It suggest Bc2 and gradually press home the advantage. Instead I went for a tempting but unsound sacrifice....

30. Bxh6 gxh6 31. Rxh6 Kg8

And black returns the favour. After Kg7 white's attack fizzles out, but now black is lost.

32. Bh5+ and black loses a rook in an awful position. 0-1.

Missed opportunities

Hennie Schaper - TheSquishKing (USA)

Caro-Kann Defence

1. e4 c6 2. d4 d5 3. e5 Bf5 4. f4 e6 5. Nf3 a6 6. Be2 c5 7. c3 Nc6 8. 0-0 cxd4 9. cxd4 Nge7 10. a3 Bg6 11. Nc3 Nf5 12. g4 Nh4 13. Nxh4 Qxh4

This looks dangerous for white, but it is actually quite safe. And what is even more remarkable: it is a won position, if only I had seen it. It's pretty basic and I really kicked myself for not spotting 14. f5 which wins the trapped bishop for a pawn.

14. Be3 Be4

Presenting me with another opportunity that I did not see and therefore did not take. This one is harder to spot though. With Nxe4 followed by d5 white opens up the centre with strong threats against the black king.

15. g5 Bf5 16. Bf3 h5 17. Ne2 Bg4

An interesting and pretty unusual position. I had the feeling that I should be able to trap the black queen with my bishops and spent lots of time thinking through potential lines, but to no avail. 

18. Bf2 Qh3 19. Bg2 Bxe2 20. Bxh3 Bxd1 21. Rfxd1 g6 

Well, that de-escalated quickly. This position is roughly equal: the bishops pair is less effective than usual given the pawn structure. I offered a draw around here, but black played on (granted, he did have far more time left than I did by now).

22. Rac1 Be7 23. Rc2 0-0 24. Rdc1 Rac8 25. Bf1 Rc7

And once again I did not profit from a black mistake. Bxa6 wins a pawn. Obviously.

26. Bd3 Rfc8 27. Kf1 Kf8 28. Ke2 Ke8 29. Ke3 Kd7 30. Be1 Na7 31. Rxc7+ Rxc7 32. 32. Rxc7+ Kxc7 33. a4 b5 34. Ba5+ Kc6 35. axb5+ Nxb5

A pretty balanced end game (indeed, the post-mortem computer analysis rates this as dead even). Black now offered a draw and I accepted. 1/2 - 1/2.

A pleasant mate

Hennie Schaper - jeffmulean (Philippines)

Sicilian Defence

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nc6 5. Nc3 a6 6. Bc4 e6 7. 0-0 Nf6 8. Re1 Be7 9. Nxc6 bxc6 10. e5

So far, things have gone in a pretty normal way for this opening. Black's response is a mistake that gives white an advantage.

10. ... Nd5 11. Bxd5 (directly Qg4 is better) cxd5 12. Qg4 Bf8 (also not the best) 13. dxe6 Qxd6 14. Bf4

White has a strong attack, with black's king still trapped in the centre. Black needed to play Qc5, but blunders instead.

14. ... Qb4 15. Nxd5 Qb7 16. Nc7+ Ke7 17. Rad1 h6 18. Bd6+ Kf6

A final inaccuracy (I would not call it a blunder, since black is totally lost anyway), but it does allow a neat finish.... I can't even remember the last time I mated with a knight.

19. Ne8 checkmate.