Contents
Introduction
This long collection is the result of computer-searching a database of games from the East Devon Congress this year (1999). I had 222 games to analyse, courtesy of Ian George who had the thankless task of bashing them all in: 111 from the Major section (U155), and 111 from the Premier (U205). Of these, exactly half were identified by Fritz 5 as having tactical blunders (see Appendix for notes on how this was done). The 111 blunders comprised 65 from the Major and 44 from the Premier.
If you would like to repeat the exercise for yourself, you can download the games from the Premier (CBH or PGN) and Major (CBH or PGN) and compare your computer's efforts to the results of my analysis (CBH or PGN).
Having had the games marked by Fritz, I then went through the games to decide which were real blunders and which were Fritz getting its wires crossed (see appendix). The resulting list of blunders I then inspected and tried to identify (a) what tactical device was at work, and (b) if there were typical errors of thinking going on. Here's an example:
(43) Boomsma B. H. - Knight S. [C07]
Major (Round 4) 1.e4 e6 2.d4 d5 3.Nd2 c5 4.exd5 Qxd5 5.Ngf3 cxd4 6.Bc4 Qd6 7.0-0 Nc6 8.Re1 Nf6 9.Nb3 a6 10.Nbxd4 Nxd4 11.Nxd4 Qc7 12.Qe2 Bd6 13.h3 "Out of Book," says Fritz. 13...0-0 14.Bd3 h6 15.c3 b5 16.Bd2 Bb7 17.a4 e5 18.Nf5 Qc6 19.Qf1 bxa4
20.Nxd6
Misses a trick.
[-0.28 Fritz 5.00: 20.Rxe5 Rad8 [not 20...Bxe5, 21. Ne7+] 21.Re7 Kh8 22.Nxd6 Qxd6 23.Re3]
Fritz assesses White's position at the end of the analysis variation as +?.?. When you dump the database out for printing, it unhelpfully strips all these assessments off, but they can be seen in the CBH database.
Psychologically, this is a missed opportunity. It is also a threat missed by Black, so both players made a mistake. Tactically, it's a decoy/overload combination, and two moves deep. I'm sure that Black overlooked the possibility of Rxe5, and missed it because it was a second effect of moving the White Queen from e2 to f1, defending against the mate on g2. My guess is that Brian also overlooked the possibility, rather than saw it and thought it a bad idea. Of course, I actually don't know enough about any of these games to be able to tell things like this for sure. Either player may have seen all this and more, although this begs the question why they didn't react to what they saw.
Three features dogged my research: these difficulties in post hoc interpretation, compounded by lack of context, and possible transcription errors. On context: some of the games I witnessed and was able to tell that one or other player was in time trouble, when some of the decisions taken might make a bit more sense. Or a player may have grabbed a draw against a higher-graded opponent. Also, I assume that the scores are accurate. Ian did mighty battle with idiosyncratic handwriting and moves scribbled in time pressure, but there are a couple of games where I can only assume some other move was played than the one recorded. (I once found a score sheet which started: 1. e4 e5 2. Nc6 Nc6 3. Nf6 Nf6 - a player new to algebraic, I concluded.)
What I have done below is a preliminary description of the blunders - a natural history, if you like, trying to classify and count my way through the range of horrors on view. The richness of chess - even this sort of chess - really requires deeper consideration than I have been able to give it so far, so please forgive this as work in progress.
Some tactics can be readily ascribed to more than one type, e.g. as above, overloading a piece defending against a fork. In these cases, I filed them under the earlier theme in the sequence.
The tactical themes found were as follows:
Left hanging:
Forks, double attacks:
Pins:
Overloading (decoys, ties):
Undermining (ties):
Unmasking (discovered attacks, jumps):
Nets (no retreat):
Mating patterns:
Queening combinations:
I suspect that these relative frequencies do not reflect their occurrence in normal play, that is, I think you are more likely to miss a fork or pin than to miss a piece hanging.
Let's see some examples, simple and more complex.
(56) Dobber P. - Duckham J. [B00]
East Devon Major 1999 (5)14.Nf3-g1
With two points: one to secure the h-Pawn...
14...Qe7 15.Qxh5
...the other of which Black missed. 1-0
(6) Jukes S. - Belinfante N. [A20]
East Devon Major 1999 (1)1. c4 e5 2.g3 Nc6 3.Bg2 Bc5 4.a3 "Out of Book," says Fritz. 4...a5 5.Nc3 Nf6 6.d3 0-0
7.Bg5 White sets himself up for a basic tactic (Knight fork 7...h6 Black didn't notice!
(2) Durrant P. E. O. - Halmkin P. E. [B07]
East Devon Major 1999 (1)21.Bh3
Black is in difficulty here but his next move makes things worse, adding a pin to the threatened discovery. In fact, White's Knight is currently pinned to the Bh3!
21...Nd7
[2.50 21...b4]
22.Nxg7
[1.66 22.Qf2]
22...Kxg7 23.Qf2 Qe8 24.Be6 Ndf8 25.Qf7+ Kh8
Suicide, as Black realises.
1-0
Skewer
(45) Halmkin P. E. - Wood J. Z. [C00]
East Devon Major 1999 (4)
Impeccable so far, says Fritz. Both sides overlook a standard skewer tactic. 48.Rg5+
[-0.56 : 48.Kd2 Rf1 49.c7 Rf8 50.Ke3 Rf3+ 51.Ke4]
48...Kf3 49.c7
[-1.28 : 49.Kd2 Ra1 50.c7 Ra8 51.Rc5 Rc8]
49...Re1
[0.81 : 49...Rc1+ 50.Kd3 Rxc7 51.Rf5+ Kg4 52.Re5 Rf7 53.Ke4]
See above, and also:
(54) Allen R. N. - Woodruff A. [C11]
East Devon Major 1999 (5)1. e4 e6 2.d4 d5 3.Nc3 Nf6 4.e5 Nfd7 5.f4 c5 6.Nf3 Nc6 7.Be3 cxd4 8.Nxd4 Nxd4 9.Bxd4 Be7 "Out of Book," says F5.. 10.Bd3 Nc5 11.Be2 Qa5 12.0-0 0-0 13.f5
13...exf5
[2.31 : 13...Bg5 14.a3]
14.b4! Qxb4
Black goes down the main line
[3.47 : 14...Qd8 15.bxc5 Be6 16.Rb1 Qc7 17.Nb5]
15.Nxd5 Qa5 16.Nxe7+
(31) Grist P. - Sparkes D. A. [B01]
East Devon Major 1999 (3)1. e4 d5 2.exd5 Nf6 3.Nf3 Nxd5 4.Bc4 "Out of Book," says Fritz. 4...c6 5.0-0 Bg4 6.d4 e6
White makes an unguarded move - or rather, an apparently guarded one.
7.Bg5
[-2.78 : 7.Nbd2]
7...Bxf3 8.Qxf3 Qxg5
Unmasking (discovered attacks, jumps):
(47) Jones R. H. - Grist P. [A01]
East Devon Major 1999 (4)
18.Nc3 Overlooking a series of masked attacks.
[-0.88 : 18.Qd3 ]
18...Nxd4 19.Na4
[19.Nxd4 Bxg2 20.Kxg2 Qxb2]
(93) Baer B. L. - Spink B. M. [A04]
East Devon Premier 1999 (4)
32...Qb1 This is the real blunder: can Black guarantee to get the Queen out? 33.Kg2 Nf6 34.Bd3 Qc1 35.Rc2 Qd1 36.Ree2 Nh5 37.Rcd2 Qa1 38.Ra2 Qc1
[6.63 : 38...d5 39.Qxd5 Nf4+ 40.gxf4 Qxc3 41.Rec2]
39.Qxf7 1-0
(71) Aston P. A. - Saqui D. A. J. [D00]
East Devon Premier 1999 (2)
White has at last worked up an attack. 30.Nh5 Allows Black an opportunity to chase away the Queen.
[-2.16 : 30.Rc3 Qd8 31.Nd3 Bg5]
30...Bf8 allows mate in three!
[#3 : 30...Rg6 31.Qe3 Qxb2 32.Nf4 Rg7 33.a3]
31.Nf6 Not only missing the mate, but walks into a defensive tactic.
[-5.13 : 31.Nxg7 surely the most natural move on the board! 31...Qxd4+ 32.Rxd4 Bxg7 33.Qxh7#]
31...Rxg2+ 32.Kxg2 Bxh6 33.Rxh6 Kg7 34.Rxh7+ Kxf6 35.h4 Qxb2+ 36.Kf3 Rb4 0-1
King safety more generally was a very common theme, sometimes in more complex situations than that. Here's one I may get into trouble for:
(101) Abbott M. - Page M. C. [D35]
East Devon Premier 1999 (5)30.Rh1
Good move! Fritz scents mate coming up. 30...Rh6
[1.91 : 30...b5 31.axb5 axb5 32.Rh3 b4 33.Ng3 f4 34.Nf5+ Kf8 35.Rh8+]
31.Ng3
[1.22 : 31.Rxh6 Kxh6 32.g4 is the way to pursue it: 32...Rf8 (32...Rh8 gives in meekly 33.gxf5 Qe8 34.Rh1+ Kg7 35.f6+) 33.Ng3 Qb6 34.Kg2 Qxd4 35.e6 fxg4 36.Rh1+ Kg7 37.Rh7+ Kg8 38.Qg6+ Qg7 39.Qxg7#]
The beginners' favourite of back rank mates made a single appearance in the register of blunders:
(76) Page M. C. - Jepps G. N. [A31]
East Devon Premier 1999 (2)
27...Re2
[4.59 : 27...Qd8 28.Qc4+ Kh8 29.Qe4 Qg8 30.Qxf4 Rxa2]
28.Qc4+
[-0.34 : 28.Rxe2 We're assuming the score is accurate, I suppose, but this looks a little better! 28...Qd8 29.Qc4+ Kh8 30.Re1 Qb8 31.Qxc6]
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(102) Evans I. D. - Dunn A. M. [C41]
East Devon Premier 1999 (5)
And a final double blunder (time pressure notwithstanding):
60.Kxg5
[-4.56 : 60.Nd1 Ng6 61.Nf2 d2 62.Kf3 Nf4 63.Ke3]
60...Ne6+
[0.00 : 60...Nh3+ and White's poor Knight does the splits. 61.Nxh3 d2 62.Nf2 h3 63.Kf5 h2 64.Ke5 h1Q 65.Nxh1]
1/2-1/2
Intermezzo
(80) Dilleigh S. P. - Frost N. A. [E15]
East Devon Premier 1999 (3)1. d4 e6 2.Nf3 b6 3.g3 Bb7 4.Bg2 Nf6 5.c4 c5 6.d5 b5 "Out of Book," says F5.. 7.dxe6 fxe6 8.cxb5 Qa5+ 9.Nc3 d5 10.0-0
10...d4 Not picked up by Fritz as an error. 11.Nxd4 Bxg2 12.Nb3
The intermezzo
12...Qc7 13.Kxg2
With another Pawn.
Attack and defence
Here, a failure to count:
(18) Herbert S. - Smith E. J. [C01]
East Devon Major 1999 (2)1. e4 e6 2.d4 d5 3.exd5 exd5 4.Bf4 Nf6 5.Nf3 Bd6 "Out of Book," says F5.. 6.Bxd6 Qxd6 7.c3 0-0 8.Be2 Re8 9.0-0 Bg4 10.Nbd2 Nbd7 11.h3 Bh5 12.Re1 Re7 13.Bd3
Black spurns an opportunity to get the advantage and instead gives up a Pawn. 13...Ne4
[0.88 : 13...Rxe1+ 14.Qxe1 Re8 15.Qf1 Qb6 16.Rb1 Qc6]
14.Nxe4 dxe4 15.Rxe4
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Thinking errors
Missed threats
One-movers
Two-movers
Three-movers
Missed opportunities (i.e. missed threat, opportunity not taken)
One-movers:
Two-movers:
Three-movers:
Oversight/natural moves in normal positions
Failure of nerve/Bluffed
Failure of analysis
Bad moves in bad positions (the frying pan problem)
Slack moves in good positions (incisiveness)
Errors of judgement not analysis (Positional errors)
Time trouble
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When our mind is on higher things, we can be laid low. Here's a few missed mates:
Candidates for blunder of the tournament must include any one-move oversights. We had more than piece left hanging and more than one mate in one.
(53) Whelan G. - Rogers D. R. [D01]
East Devon Major 1999 (4)
50.Nf1 Suicide.
[-#1 : 50.Kf1 a5 51.Rb8 h4 52.Rf8+ Ke7 53.Rg8]
50...Re2# 0-1
(52) Steer G. - Neilsen J. H. [A45]
East Devon Major 1999 (4)
25... Qd7
[#1 : 25...Rxe1+ 26.Rxe1 Qg4 27.h3 Qg5 28.Nf3 Qf6]
26.Qg6# 1-0 Oops.
In my youth such things were referred to as cheapos - a point gained through minimum effort. It's hard to describe these as two moves deep, more like two moves shallow!
(66) Dunn A. M. - Aston P. A. [A00]
East Devon Premier 1999 (1)
16.a3 Not best.
[-#3 : 16.e4 Nxd3+ 17.Bxd3 Bxa2 18.Rd1 Qe5 19.h4 Rd8 20.Qg5 Qxg5+]
16...Nxd3+ 17.exd3
[17.Kd1 Qe1#]
17...Qe1# 0-1
(98) Regis D. - Piper S. J. [B47]
East Devon Premier 1999 (4)32.Rf3
Black is under the cosh, but loses instantly:
32...Qe4
[#3 : 32...Nf4 33.Qf5+ Ng6 34.Nxf7 Bf4 35.Qh5+ Kg8 36.Rg1 Rab8 37.Nh6+]
33.Nf5+ (threat Ne7+) 1-0
What produces these errors?
One obvious theme is a move of the opponent with two points, one of which you miss.
Another is mood: a player ahead on material or with a strong attack may overlook opportunities for the defending side. Or a player who is being attacked may panic and find it difficult to focus on simple threats of the opponent, or become gloomy and stop looking.
Missed opportunities (i.e. missed threat, opportunity not taken)
White overlooks a tactic made possible by Black overlooking the threat - so every missed opportunity may also represent an error of the opponent, allowing you to carry out a threat that could have been prevented.
We can find examples of every depth, as above:
(11) Webley M. A. - Spiller P. [C21]
East Devon Major 1999 (1)
A curious double oversight follows. 29...Bf3 That Bishop is en prise!
30.Kf2
White misses it!
Most people's idea of a one-mover is more like this:
(29) Foulds A. - McFarlane P. [A69] East Devon Major 1999 (3)
18...f6 ? 19.Rab1 ?
[-3.31 : 19.Qd5 forward! ]
(5) Ingham W. - Pinder R. [A07]
East Devon Major 1999 (1)
12.b4 Fritz reckons this a blunder
[-0.91 : 12.Qe2 ]
12...Nc6 with double attack on b4 and e5 13.a3 cxb4
(35) Rogers D. R. - Price C. R. [A15]
East Devon Major 1999 (3)17.Bc3
Both sides get in a muddle here: Black need not shed a piece, and has a clever alternative. 17...Bxd4+
[2.88 : 17...Qxc3 neat, eh? 18.Nxc3 Bxd4+ 19.Qxd4 cxd4 20.Nd5]
18.Qxd4 of course
This is sort of a three-mover:
(14) Belinfante N. - Wood J. Z. [C11] East Devon Major 1999 (2)
Black now plays a series of moves which make a poor position fatal. 14...f6
[1.94 : 14...b4 15.Nb1 Qxc2 16.Bd3 Qc7 17.Nbd2]
15.exf6
Natural, but risking letting an opportunity slip.
[0.06 : 15.Nxd5 exd5 16.Qxd5+ Kh8 17.exf6 Bxf6 18.Qxa8 Bxb2]
15...Bxf6 ? Overlooking White's idea
[1.03 : 15...Nxf6 16.Bd3 Bd6 17.Ne5 Nd7 18.Nxd5 Bxe5 19.Nxc7 Bxd4 20.Nxa8]
16.Nxd5 back on track 16...exd5 ? Unnecessary! White must have some idea in mind, and there's no need here to fall for it.
[2.81 : 16...Qxc2 17.Nxf6+ Nxf6 18.Bd3 Qc7 19.Qe5 Nd5 20.Qxc7 Nxc7]
17.Qxd5+ Kh8 18.Qxa8
That opportunity was only taken because it was re-presented.
After this, I suspect we are at the limit of what many players can analyse accurately without mistakes. Given a favourable wind, we might follow a given sequence some ten moves deep, but not reliably identifying or analysing all the alternative branches. Still, see if you can do better than the tournament winner here:
(89) Saqui D. A. J. - Baer B. L. [E61] East Devon Premier 1999 (3)
27.g3 This weakening move sets Black up for a stock mate.
[-#5 : 27.R7a2 Bg5 28.h3 Qxh3+ 29.gxh3 Rxh3+ 30.Kg2 Nh4+ 31.Kg1 Nf3+]
27...Qh3 Sufficient but the game could have been decided simply:
[-7.66 : 27...Qxh2+ 28.Nxh2 Bxe3 29.Bf8+ Rcxf8 30.Kg2 Rxh2+ 31.Kf1 Rxf2#]
28.Ne2
[-#4 : 28.Qxd5 Bxd5 29.Rxc7 Bc4 30.Rxf7+ Kxf7 31.Nxe4 Bxf1]
28...Bxe3 29.Ng1 Qxh2+ 0-1
Oversight/natural moves in normal positions
We can see the fatal attraction of 'normal' moves in the games Dobber-Nielsen and particularly Belinfante-Wood. Here's another:
(21) Laurain F. - Whelan G. [B07]
East Devon Major 1999 (2)
13.Ba3
[-1.00 : 13.Rb1 Re8 14.Be3 Bc6 15.Rfd1 Qxd6 16.Rxd6]
13...Re8 Now White has chased the Rook to e8, he has pieces en prise on both e2 and a1!
(32) Jukes S. - Scott R. [A24]
East Devon Major 1999 (3)1. c4 e5 2.Nc3 Nf6 3.g3 g6 4.Bg2 Bg7 5.b4 "Out of Book," says Fritz. 5...c6 6.Rb1 0-0 7.d3 d5 8.Bg5 Be6 9.cxd5 cxd5 10.Qd2 Re8 11.Nf3 Qd6 12.0-0 a6 13.Rfc1 Nbd7 14.Rc2 Nb6 15.h3 Rec8
16.Nxe5 enterprising but flawed?
[-1.81 : 16.Rbc1 d4 17.Bxf6 dxc3 18.Qg5 Bxf6 19.Qxf6]
16...d4 Black is bluffed!
[0.25 : 16...Qxe5 A) 17.Bf4 must have been White's idea: 17...Qh5 18.Bf3 (18.g4 Nxg4 19.hxg4 Bxg4 20.e3 Bf3 21.Bxf3 Qxf3) 18...Qxh3 19.Bg2 Qh5 20.Bf3 Bg4;
Hard to see to the end, but there's no concrete line to follow up.
[ B) 17.Qe3 17...Nfd7 18.Qxe5 Nxe5 19.Rbc1 d4]
These are among the most interesting blunders, requiring a certain level of chess competence to achieve. Sometimes the failures are simple - like failing to count - and others are more involved.
(46) Herbert S. - Dobber P. [B07]
East Devon Major 1999 (4)
12.Nxe5 An attractive but flawed idea.
[-0.72 : 12.Bc4 b5 13.Be2 Nd7 14.Bh4 Nc5 15.Nxe5 Bb7 16.Bg3 Nxe4]
12...f6
Oops.
(3) Foulds A. - England M. C. [E76] East Devon Major 1999 (1)
White's next is a bright idea laid low by a miscalculation. 15.Nxd5
[-3.09 : 15.Nf3 Bxc3 16.bxc3 Nc7 17.bxa6 Bxa6 18.Bxa6 Rxa6 19.a4]
15...Nxd5 16.Bc4 Nef6 17.Qf3 e6 18.Re1 Re8
(72) Bolt G. - Talbot A. R. [B86] East Devon Premier 1999 (2)
1. e4 c5 2.Nf3 d6 3.Bc4 Nf6 4.Nc3 e6 5.d4 cxd4 6.Nxd4 a6 7.a4 Be7 8.Bb3 "Out of Book," says Fritz. 8...0-0 9.0-0 Nc6 10.f4 Qc7 11.Kh1 Bd7 12.f5 Nxd4 13.Qxd4 e5 14.Qd3 Bc6 15.Bg5 Rad8 16.Rae1
A thematic break, but is it sound? 16...d5 17.Qg3 Bluffed!
[-0.47 : 17.Bxd5 h6 18.Be3 Ng4 19.Bd2 Bc5;
17.exd5 Nxd5 18.Bxe7 Nxe7 19.Qe2 also wins a Pawn;
17.Nxd5 is the most obvious line to analyse, and it is not bad for Black: 17...Nxd5 18.exd5 Bxg5 19.Qg3 Bxd5 20.Qxg5]
I put this one under 'analysis' rather than the similar example above which was 'bluffed'; this one is a short line which I guess White failed to analyse, the one above was a long line which I'm sure Black looked at but feared ending badly.
Bad moves in bad positions (the frying pan problem)
The phrase 'bad moves in bad positions' is from Hugh Alexander. Partly this is statistical: when you stand worse, fewer of your moves will not lead to trouble. One can have sympathy. But it is also psychological: panic, depression or a general lowering of expectations can all cause decision-making and chosen moves to become poorer. I saw loads of these...
(9) Speigel J. A. - Laurain F. [B26]
East Devon Major 1999 (1)20.Rae1
20...Be7 Making a bad situation worse.
[2.09 : 20...Bc7 21.Rf6 h4 22.d6 hxg3+ 23.Kxg3 Bd8 24.Rxe5+ Kf8 25.Rf4]
21.Rxe5
21...f6 Not cutting his losses.
(5) Ingham W. - Pinder R. [A07] East Devon Major 1999 (1)
13...cxb4
14.Qb3 makes the worst of a bad job
[-2.56 : 14.Bb2 ] Â
Slack moves in good positions (incisiveness)
This was almost as common as the 'bad to worse' pattern: not really being in top gear when looking at a favourable position. There are many factors at play here: nerves, complacency, laziness and more.
(29) Foulds A. - McFarlane P. [A69]
East Devon Major 1999 (3)
When you see a good move, stop and think again... 22.Qxa8
[-2.00 : 22.Bh6 ...There might be a better one! This move gets the Bishop off the hook with tempo 22...Re7 23.Qxa8 Bxh2 24.Rbd1 Qe5]
(5) Ingham W. - Pinder R. [A07] East Devon Major 1999 (1)
14.Qb3 makes the worst of a bad job
[-2.56 : 14.Bb2 ]
14...bxa3 Black does not exploit his advantage in the best way.
[-1.19 : 14...Nc5 15.Qa2 Nxd3 16.Rd1 Nxc1 17.Raxc1 bxa3 18.Nxd4 Nxe5]
(One game with three characteristic blunders!)
(64) Stanners M. J. - Price M. C. [D00]
East Devon Major 1999 (5)16.a4
16...0-0-0 Into the fire.
[2.44 : 16...f5 17.axb5 fxe4 18.Nxe4 Qc7 19.bxc6]
17.axb5 Nxd4 18.Rxa7
[0.59 : 18.Nxc4 is rather better 18...Nxf3+ 19.Qxf3 Qc5+ 20.Kh1 Qxc4 21.Qxf4 Qc5 22.Qxf7]
Errors of judgement not analysis (Positional errors)
Fritz can occasionally identify a move as a blunder, as far as I can tell on positional grounds. Sometimes I agree with it!
Here's an example of what I mean:
(38) Speigel J. A. - Kennedy P. J. [B26]
East Devon Major 1999 (3)
20.0-0 allows Black to seize the seventh
[-1.09 : 20.Rd2 Nc6 21.0-0 Ke7 22.Rfd1 Rhd8]
20...Rb2 21.Rfe1 Rxa2
More typical are positional errors Fritz ignores:
(1) Dobber P. - Nielsen J. H. [B01]
East Devon Major 1999 (1)1. e4 d5 2.exd5 Qxd5 3.Nc3 Qa5 4.d4 c6 5.Nf3 Bf5 6.Be2 e6 7.0-0 Nf6 8.Re1 "Out of Book," says Fritz. 8...Nbd7 9.h3 Be7 10.Bf1 0-0 11.Nh4
Black mistakenly allows White to secure the two Bishops and a Queen's-side majority. 11...Rfe8 12.Nxf5 exf5
Time control here was at move 40, so any game which degenerates around move 35 or even earlier could be due to clock pressure. Time trouble doesn't provide a complete explanation for out-and-out blunders, but it does produce them. We saw one I guess in Evans-Dunn.
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Conclusions and recommendations
Well, what do you think?
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Appendix: on working with a computer
I haven't done this sort of thing before and wondered if those attempting a similar exercise might find the following notes helpful.
I analysed all the games using the 'blundercheck' feature of Fritz 5. I used the default settings of time 10, (seconds I think) and a criterion of 60 (a difference of more than half a Pawn [100]). Left to run overnight, Fritz identifies better lines and flags each game containing a blunder with a black spot, which it describes as a "medal". These settings seem to result in a depth of about depth of 10-ply (5 whole moves by White and Black).
I assume these defaults are generally OK, but I don't know if anyone has found a better combination of settings.
Fritz takes the instruction to look for only ten seconds very seriously. That is, Fritz is capable of assessing a position after Black's fifth move as favourable to Black, even if White's sixth move delivers checkmate!
Proof: in this position...
(72) Bolt G. - Talbot A. R. [B86]
East Devon Premier 1999 (2)
...Black came up with a creative way to lose a piece, which Fritz assessed at +3.22 for White:
32...Qxh3 33.gxh3 Nf3 34.Qxe3 Nxe1 35.Qxe1
Fritz preferred the move:
32...Rge8 when it analysed: 33.Rhxe3 Rxe3 34.Qxe3 Nxb3 35.Qxb3 Rxd6 36.Re8+ Kh7 37.Qxb7, after which 10 ply it assessed the position as only 0.81 to White - how would you assess it?
(e
Perhaps because of this, often the majority of Fritz' comments occur only towards the end of the game, when the result has been all but decided.
(25) Scott R. - Bloom P. [B46]
East Devon Major 1999 (2)White has just played 47. b4 to reach this position:
The previous 46 moves by White and Black escaped calumny, but now Fritz got all interested:
47...Bb6
[17.81 Fritz 5.00: 47...Qe3 48.bxc5 Qxc5 49.Qg6 Qf8 50.a7 Qg8 51.Qf7 Rf8 52.Qxf8 +13.63]
48.c4
[10.78 Fritz 5.00: 48.Qg6 threat Be4 is better 48...Rxe6 49.Qxe6 Qe3 50.Qc8+ Kh7 51.Qf5+ Kg8 52.a7 Qe8 +19.41]
48...Bd8
[24.91 Fritz 5.00: 48...Qe3 49.c5 Qxe4 50.Bxe4 Bc7 51.a7 Be5 52.a8Q Rxa8 53.Bxa8 +12.22]
49.Qd4
[11.34 Fritz 5.00: 49.Qg6 idea Be4 is better 49...Qxf3 50.Qxe8+ Kh7 51.gxf3 Bb6 52.Qc6 Bd4 53.e7 Bf6 +27.88]
49...Qh4 50.Qxh4 Bxh4 51.a7 1-0
So, a "blunder" in Fritz' terms (a better move was available with an outcome a Pawn's worth different), but in practical terms, who cares? Incisiveness in critical positions is important, but this finale was hardly critical. Some of the 111 games with blunders were like this one. Meanwhile the phase of the game where Black failed to castle, got in a horrid pin and shed all his Queen's-side Pawns and a piece, is passed over in silence.
Fritz, like many computers, likes the bird in the hand more than many players. Undoubtedly, if it did not have an opening book it would not accept for a moment any gambit, especially long-range ones like the Benko.
(82) Hodge D. - Hammond T. J. [A35]
East Devon Premier 1999 (3)1. e4 c5 2.c3 g6 3.d4 cxd4 4.cxd4 d5 5.exd5 Nf6 6.Nf3
6...Bg7
Typically Fritz does not like to be without material, and prefers 6...Nxd5.
(3) Foulds A. - England M. C. [E76]
East Devon Major 1999 (1)1. d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.f4 0-0 6.Nf3 c5 7.d5 Nbd7 "Out of Book," says Fritz. 8.Be2 a6 9.0-0 b5
Fritz doesn't like giving up Pawns, but this Benko-style idea looks perfectly legitimate.
[0.94 : 9...b6 10.Qc2 Bb7 11.Be3 Qc7 12.f5 gxf5 13.exf5]
Also, very practical attempts to open or muddle the position are nearly always criticised. [We need to understand the 'nearly'; it may be in these positions the compensation is obvious even to a stupid computer.]
(71) Aston P. A. - Saqui D. A. J. [D00] East Devon Premier 1999 (2)
1. d4 Nf6 2.Nc3 d5 3.e4 dxe4 4.f3 Bf5 5.fxe4 "Out of Book," says Fritz. 5...Nxe4 6.Qf3 Nd6 7.Bf4 Qc8 8.Bxd6 cxd6 9.Bb5+ Bd7 10.Nh3 a6 11.Bxd7+ Nxd7 12.Nd5 Qc6 13.0-0 Nf6
14.c4 This perfectly reasonable attempt to pursue an initiative is queried by Fritz.
[-1.44 : 14.Nhf4 Rc8 15.c3 e6 16.Nxf6+ gxf6 17.d5]
A positive side of Fritz' materialism is a healthy scepticism about sacrifices; if it can't see a mate, it fancies the material.
(10) Stanners M. J. - Sellwood C. [D00]
East Devon Major 1999 (1)1. d4 Nf6 2.e3 "Out of Book," says Fritz. 2...e6 3.Bd3 c5 4.f4 Nc6 5.c3 d5 6.Nd2 Qc7 7.Qf3 cxd4 8.exd4 Bd6 9.Nh3 0-0 10.0-0 b6 11.Ng5 h6
12.h4
Computers can take the fun out of playing sacrifices. Fritz is unimpressed by White's intentions to deliver mate and fancies grabbing the material.
[-1.78 Fritz 5.00: 12.Nh3 -0.31]
12...Bb7
Bluffed!
[-0.41 Fritz 5.00: 12...hxg5 13.fxg5 (13.hxg5 Nh7 14.Qh5 g6 15.Qh6) 13...Nd7 14.Qh5 g6 15.Qf3 -1.53]
Fritz, like many computers, cannot appreciate positional sacrifices. These are not easy for club players to contrive except in certain familiar situations but when they were offered Fritz poured scorn on nearly all of them.
(86) Pinkerton A. - Aston P. A. [A44]
East Devon Premier 1999 (3)1. d4 c5 2.d5 e5 3.g3 "Out of Book," says Fritz. 3...d6 4.Bg2 Be7 5.Nc3 a6 6.a4 h5 7.e4 h4 8.g4
8...h3
[0.75 Fritz 5.00: 8...Bg5 -0.13]
As usual, positional Pawn sacrifices are not to Fritz' taste.
Again, the 'nearly all' is interesting: sometimes it must have recognised some of the compensation and did not jump on the move as an error.
(81) Hewson B. W. R. - Jaszkiwskyj P. [D53]
East Devon Premier 1999 (3)1. c4 e6 2.Nc3 Nf6 3.d4 d5 4.Bg5 Be7 5.e3 0-0 6.Bxf6 "Out of Book," says Fritz. 6...Bxf6 7.cxd5 exd5 8.Bd3 c6 9.h4 Re8 10.Nge2 Bg4 11.Qc2 g6
12.h5 One Pawn sacrifice that even Fritz doesn't query!
There is a particular class of move that Fritz always labels a blunder and with which calumny I cannot agree: the simplifying move or combination. This may reduce your attacking force, or even give up some of your material advantage, but still be an excellent idea.
(7) Price M. C. - Sparkes D. A. [C14]
East Devon Major 1999 (1)
62.Rxe6+ Just the sort of clarifying sacrifice a human likes and computers hate. In fact, both the Knight and King are perilously short of squares and can each be profitably harassed.
[#7 Fritz 5.00: 62.Qg3 Ng2 (62...Nd5 63.Rxe6+ Kc5 64.Qg1+) 63.Qxg2+ Kc5 64.Kc3 f4 65.Rxe6 f3 66.Qxf3]
Positional blunders by computers
We are used to positional mistakes being overlooked by computers, but we can also see positional errors being positively suggested by Fritz. Here's one:
(89) Saqui D. A. J. - Baer B. L. [E61]
East Devon Premier 1999 (3)
A standard reversed KIA position (Pe3 not Pe4) where Black will want to deliver mate soon.
21.Kh1
[-0.16 Fritz prefers 21.a6 which removes any shred of White counterplay!]
There are occasions when I cannot fathom what is going on in Fritz' twisted little silicon mind.
(27) Woodruff A. - Jukes S. [E12]
East Devon Major 1999 (2)
29...Rdb7
I don't understand Fritz' querying this move, even though I see no very compelling reason for it.
[-0.88 Fritz 5.00: 29...Rd8 30.h5 Ke8 31.Kf1 Rd7 32.Ke2 a4 33.Rd2 Rdb7 34.Rd4]
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Blunders at East Devon
Tactical themes
Left hanging:
Forks, double attacks:
Pins:
Overloading (decoys, ties):
Undermining (ties):
Unmasking (discovered attacks, jumps):
Nets (no retreat):
Mating patterns:
Queening combinations:
Thinking errors
Missed threats
One-movers
Two-movers
Three-movers
Missed opportunities (i.e. missed threat, opportunity not taken)
One-movers:
Two-movers:
Three-movers:
Oversight/natural moves in normal positions
Failure of nerve/Bluffed
Failure of analysis
Bad moves in bad positions (the frying pan problem)
Slack moves in good positions (incisiveness)
Errors of judgement not analysis (Positional errors)
Time trouble
Conclusions and recommendations
Appendix: on working with a computer
Method
Horizon effect
When victory is in sight
Materialism
Positional sacrifices
Simplifying sacrifices
Positional blunders by computers
Crossed wires
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