Here is a position from one of my correspondence games:

tactics

White to move,  win.  Just in case, the answer in in the comment.

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I just ran an OTB game that I played a year ago through Fritz 11 using “Blundercheck” mode and Fritz showed me an interesting possibility that I missed.  Here is the combination that I didn’t see.  I am White, the position arised from  Owen Defense – 1.e4 b6.

Pos1

White to move,  I played 14. Qe4.  Fritz suggests better move,  quite paradoxical – 14. Rfd1! and after 14. … Bxd1 15. Rxd1 Rad8 Rad8 16. Bxh7+ getting ~1.50  advantage.

Pos2

What about 15. … Rxd1 Rad8 16. Qe8 ? Then follows 16. Qe4 g6 17. Bb5

Pos3

getting 2 pieces for the rook.

I just liked the combination of several tactical motifs here – discovered attack (Bh7+),  double attack ( Qe4, though literally the knight is still defended by the Queen) and pin (Bb5).  As for the weaknesses, we see:

  1.  h7
  2.  White occupies important b1-h7 diagonal,
  3. White can occupy “d” vertical (by using sacrifice!).
  4. Knight  on C6 not very stable,  can also be pinned

In the game I tried to use 1 and 2, then 4.   Fritz used all 4 at once.

Pos2I run some of my online blitz games through Fritz, using “Blundercheck” mode.
It finds not blunders, but also any missing tactics, actually anything that’s worse
than Fritz’s preferable move by 0.75 pawn ( of course you can change that range).
Here is the combination, that I didn’t see, the position is from Caro-Kann defense,
fantasy variation that was suggested by GM Bareev in his lecture.
Pic 2
White to move, computer suggests Bh6. OK, but why the reply is Rf8?
Strange, right? What if, let’s say, Nc6? Fritz says – Rxf7!
Pic 3
If Kxf7, then Rf1+, Kg8, Qxe6+ and Bg7#.
So, after Rf1+, Black has to give up on f6 first his bishop, then his queen,
leaving Black with 2R+N vs. Q+B+N+P and score 7.45.
The second example is easier, I hope you find the solution ( just in case it’s in the comment).

I run some of my online blitz games through Fritz using “Blundercheck” mode.  It finds not only blunders, but also any missing tactics,  actually anything at all that’s worse than Fritz’s preferable move by 0.75 pawn ( of course you can change that range).

Here is the combination that I didn’t see.  I am White, the position is from Caro-Kann defense, fantasy variation that was suggested by GM Bareev in his lecture – 1.e4 c6 2. d4 d5 3. f3.

Pos2

White to move, computer suggests Bh6.  OK, but why the reply is Rf8? Strange, right? What if black plays,  let’s say,  Nc6?  Fritz says – Rxf7!

Pos3

If Kxf7, then Rf1+  Kg8, Qxe6+

Pos4

Kh8, Bg7#.

So, after Rf1+ Black has to give up on f6 first his bishop, then his queen, leaving Black with 2R+N vs. Q+B+N+P and score 7.45.

The second example is easier,  White to move and win material, just in case the solution is in the comment.

Pos1

Another G/15 on FICS,  I play Black, this time I found it. Interesting that first 3 moves I wanted to play were right,  then 4th move was actually leading only to perpetual, but there is a winning move here as well.  I didn’t get there because he played 3rd move differently,  it was move losing quickly.  I think OTB I would see the right continuation, maybe straight from the beginning.

Can you see the both lines,  winning and perpetual?  Just in case, the answer is in the comment. Black to move:

tactics2

I played recently this game (G/15) on FICS,  had a good attack after sacrificing a bishop, but din’t find the winning move.  Can you see it?  White to move:

tactics

Just in case, the solution is in the comment.

I am reading the book  “Combinations in the Middlegame” written by Igor Bondarevsky,  Soviet Grandmaster in both over-the-board and correspondence chess,  an International Arbiter, a trainer, and an author of chess books.  Bondarevsky shared the 1940 Soviet Championship title, and later coached World Champion Boris Spassky.  In the Chapter II: Combinational Ideas I found an interesting motif that I didn’t see ( and couldn’t find) anywhere else – seizing a point.

Sacrifice with this motif serves  purpose of, as the name says, seizing an important point, then having that point the active side plays some forced line(s).

The first example is from the game Razuvaev-Briem,  Puerto-Rico, 1971:

point1

25. Qg5 – this one move threat forces Black to block his King. 25.  … Rg8 26. Nd6!

point2

The queen is sacrificed to seize the decisive point. The knight creates the final threat, more exactly triple threat – mate on f7, Nxb7 and Nxc8, there is no defense.

Another example is from the game  Fisher-Sofrievsky, Scople, 1967:

point3

The positon of the Black king is weak, it gives an idea to find some tactics to use it.  15. Nd5!  The knight is sacrificed to get for the rook square d5. After 15.. exd5 16. Rxd5

point4

16. … Qa6 ( 16. … Qb4 17. a3 )  17. Rh5 White wins quickly.  

In the game Black didn’t accept the sacrifice, played 15. … Rfe8. Then followed 16.  Nxe7 Rxe7 17. Rxd6 and White got  easily won position.

This Sunday I played in the local club,  my regular G/90.

The game had the final similar to the one that I had with the same opponent 3 months ago ( his rating at that time was about the same as mine, now 130 less),  the opening was the same. The coincidence looked funny, so I decided to showcase both.

I played White, Sicilian, Rossolimo variation.

First game:

1. e4 c5 2. Nf3 Nc6 3. Bb5 a6 4. Bxc6 bxc6 5. d3 d5 6. Nc3 Bg4 7. h3 Bh5 8. Bf4 e6 

vert1

Crafty wants me to play 9. g4 here with 0.66, my move gets 0.5 less.

9. Qe2 d4 10. Nd1 Nf6 11. b3 c4 12. O-O c3 13. a4 Be7

vert2

14. Kh2 O-O 15. Rg1 Bd6 16. Bxd6 Qxd6+ 17. Kh1 Nd7 18. g4 Bg6

vert3

19. Nh4 e5 20. f3 Nc5 21. Nf2 Ne6 22. Nf5 Bxf5 23. gxf5 Nf4

vert4

24. Qf1 f6 25. Ng4 Kh8 26. Kh2 c5 27. Qf2 a5 28. Rae1 Ra7 29. Qh4 Rb7 30. Nf2 c4 31. bxc4

vert5

Crafty thinks, that I made a mistake and 31. dxc4 is much better  ( I agree ) – 31. dxc4 Qa3 32. Ra1 Qc5 33. Rad1 Ne2 34. Rg4 Kg8 35. Nd3 -with estimate  0.75.  I didn’t like 31. dxc4 d3, but White just plays 32. Nxd3 Nxd3 33. Rd1 Qa3 34. Rxd3 – 3.51.

31. bxc4 Rg8 32. Rg4

vert6

I am clearly worse and trying this chance.  32. … Rb2  He doesn’t see it. 33. Qxh7+!  

vert7

33. … Kxh7 34. Rh4+ 1-0 ( 34. … Nh5 Rxh5#).

vert8

Second game:

1. e4 c5 2. Nf3 Nc6 3. Bb5 a6 4. Bxc6 bxc6 5. d3 d5 6. Qe2 g6 7. O-O Bg7 8. Nbd2 e6

vert9

9. Nb3 Qb6 10. Rb1 Ne7 11. Bg5 a5 12. c3 a4 13. Nbd2 Ba6 14. Rfc1 Ra7 15. b4! – one of the plans in this variation, here it has also tactical ground. My opponent spent quite some time here.

vert10

15. … O-O 16. bxc5 Qa5 17. e5 Rc7 18. Be3 Nf5 19. c4 Rd8 20. Bg5 Rdd7 21. cxd5 Rxd5 22. Nc4 Bxc4 23. Rxc4 Rxc5

vert11

Crafty says it’s a big mistake  because of 24. Rb8+ Bf8 25. Bd2! Qa7 26. Rxf8+ Kg7 27. Ra8 Qxa8 28. Rxc5 Qf8 29. Rc4 a3 30. Bg5 – score 4.85.

24. Rxc5 – I don’t see it too. 24. …Qxc5 25. Rb8+ Bf8 26. Qb2 h6 27. Bd2 – now I see it. He sees it too and again spends essentual time.

vert12

27. Bd2 Qa7 28. g4 Ng7 29. Bxh6 Kh7??

vert13

30. Rxf8 Kxh6??  31. Rh8# 1-0

vert14

I think the time played it’s role (29minutes/19 minutes), still remembering the first game it all looks like some kind of blindness with regards to that specific vertical/type of mate,  chessloser used an interesting word – “chessblind” when he didn’t see the move.