chessgames.com
 
Chessgames.com User Profile Chessforum
agb2002
Member since Jun-28-08 · Last seen Apr-23-14
I'm an applied mathematician who lives in the south east of Spain. I'm not rated.

My favorite players are those considered the best endgame artists of all time: Lasker, Rubinstein, Capablanca, Smyslov and Fischer. I also tend to prefer the strategists (Botvinnik, Karpov, Kramnik) and the universal style players (Spassky, Anand) to the tacticians. However, I like accurate chess regardless of the players and styles.

My approach to the puzzles is similar to that of David Zechiel (User: dzechiel): I first write the variations I find in a reasonable amount of time (using the puzzle diagram only) and post them before watching the game or other's comments. Then I have a look at them and try to be critical with my work. I apply the touch-move rule to my posts (see Unzicker vs Fischer, 1960). I hope to improve my tactical vision this way.

Often I cannot even spend a couple of minutes looking at the diagram (work, family, other interests, etc.) so I try to blind solve it along several breaks. My first attempt was R Vera vs S Garcia-Martinez, 2001 and although the variations I found were not very deep I felt quite satisfied with the experience.

I became interested in puzzle Elo ratings after trying to find a way of measuring my progress with these exercises. However, computing just rough estimates of the Elo rating of a given puzzle is a difficult problem. Some strategies to accomplish this are:

I. Machine estimates. This method is pursued by User: MostlyAverageJoe so you should refer to his forum for further details.

II. FIDE Elo distribution. This method assumes that the following more or less reasonable assumptions hold:

1) The puzzle kibitzer Elo distribution is close enough to that of FIDE rated players.

2) A player with Elo x is a good representative of the players belonging to the Elo interval [x-25, x+24].

3) Kibitzers are objective and only claim the point when they really worked out the complete solution.

I have approximated the FIDE Elo distribution with this table (source http://www.fide.com, Dec 31 2008):

__A_ | __B_ | __C_ | __D__ | __E__ | ___F___
1325 | 1300 | 1349 | 99209 | ____0 | 100.0000
1375 | 1350 | 1399 | 99209 | ____0 | 100.0000
1425 | 1400 | 1449 | 99209 | __185 | 100.0000
1475 | 1450 | 1499 | 99024 | __373 | _99.8135
1525 | 1500 | 1549 | 98651 | __558 | _99.4376
1575 | 1550 | 1599 | 98093 | __850 | _98.8751
1625 | 1600 | 1649 | 97243 | _1286 | _98.0183
1675 | 1650 | 1699 | 95957 | _1851 | _96.7221
1725 | 1700 | 1749 | 94106 | _2594 | _94.8563
1775 | 1750 | 1799 | 91512 | _3511 | _92.2416
1825 | 1800 | 1849 | 88001 | _4677 | _88.7026
1875 | 1850 | 1899 | 83324 | _5879 | _83.9883
1925 | 1900 | 1949 | 77445 | _7053 | _78.0625
1975 | 1950 | 1999 | 70392 | _8236 | _70.9532
2025 | 2000 | 2049 | 62156 | 10602 | _62.6516
2075 | 2050 | 2099 | 51554 | 11189 | _51.9650
2125 | 2100 | 2149 | 40365 | 10541 | _40.6868
2175 | 2150 | 2199 | 29824 | _8745 | _30.0618
2225 | 2200 | 2249 | 21079 | _7531 | _21.2471
2275 | 2250 | 2299 | 13548 | _5311 | _13.6560
2325 | 2300 | 2349 | _8237 | _3358 | __8.3027
2375 | 2350 | 2399 | _4879 | _1993 | __4.9179
2425 | 2400 | 2449 | _2886 | _1367 | __2.9090
2475 | 2450 | 2499 | _1519 | __643 | __1.5311
2525 | 2500 | 2549 | __876 | __451 | __0.8830
2575 | 2550 | 2599 | __425 | __238 | __0.4284
2625 | 2600 | 2649 | __187 | __109 | __0.1885
2675 | 2650 | 2699 | ___78 | ___46 | __0.0786
2725 | 2700 | 2749 | ___32 | ___20 | __0.0323
2775 | 2750 | 2799 | ___12 | ___11 | __0.0121
2825 | 2800 | 2849 | ____1 | ____1 | __0.0010
2875 | 2850 | 2899 | ____0 | ____0 | __0.0000

where column A is the Elo representative of the class of players determined by columns B and C, column D is the amount of players stronger or equal, column E is the amount of players in the corresponding class and column F is the percentage of players stronger or equal.

Now, if, for example, 70% of us solved completely the puzzle, I would rate it at Elo 1975 or better, between 1950 and 1999 points.

Unfortunately, not all of us publish (an excerpt of) our findings to 'prove' that we got the solution (or a terrible embarrassment...). This translates into many computational problems: from strong bias (as pointed out by John Spouge, see agb2002 chessforum) to such lack of resolution that assessing the more difficult puzzles becomes impossible (see agb2002 chessforum).

III. Puzzle characteristics. There are some features in every puzzle that can be used as metrics to evaluate its difficulty, for example, the type and number of tactical motifs, the number and depth of variations, the type and amount of material still on board, etc. For example, many players will solve the following puzzle immediately (White to move, Lasker's Manual of Chess, p. 116):


click for larger view

However, the next puzzle is considerably more difficult in spite of containing practically the same tactical motifs (White to move, Lasker's Manual of Chess, p. 119):


click for larger view

Once having collected a sufficient number of puzzles with their metrics and Elo evaluation (perhaps using method I) it might be possible to fit a several variable function in which the independent variables are the metrics and the dependent variable is the given Elo rating.

IV. Post characteristics. We can try to use some metrics from the posts to estimate its rating. These metrics would include:

1. CG assigned stars.
2. Posts issued on the puzzle's day.
3. Posts recognizing failure.
4. Plies to reach a clear decision, draw included.
5. MostlyAverageJoe's rating (thanks MAJ!).
6. Posts claiming (or implying) it was (too) easy.
7. Posts complaining (or implying) it was (too) difficult.

Once having collected enough data (from at least 30 puzzles) we would try to find the most suitable fitting model f:

rating = f(x1, ..., x7)

xi being the above variables, not necessarily all included in the model. For example, it could be as simple as

rating = 1200 + 100*plies

As a curiosity, this is a VBA function for the best fitting model I've found to date using the CG stars (cgs) as the only predictor variable (N = 181, Rē = 0.688, asymptotic standard errors five times -at least- smaller that the corresponding coefficients):

Function MAJ_Rating(ByVal cgs As Double) As Double

Const a As Double = 861.15488885
Const b As Double = -0.555156265
Const c As Double = 0.156127404
Const d As Double = -0.015186844

MAJ_Rating = a / (1 + cgs * (b + cgs * (c + cgs * d)))

End Function

Comments are welcome.

>> Click here to see agb2002's game collections.

Chessgames.com Full Member

   agb2002 has kibitzed 2826 times to chessgames   [more...]
   Apr-23-14 Carlsen vs Radjabov, 2014 (replies)
 
agb2002: Carlsen has many chances of recovering the first place by beating Radjabov.
 
   Apr-23-14 Caruana vs Carlsen, 2014 (replies)
 
agb2002: Caruana can try now 23.Rd1 threatening 24.Nb5 a6 25.Nxc7 Kxc7 26.e6+.
 
   Apr-23-14 M Richter vs E Berg, 2011 (replies)
 
agb2002: Black has a knight for a rook. White is putting pressure on Black's b-pawn. White's back rank is poorly protected and the white queen is defenseless. This invites to play 36... Rc1+ 37.Rd1 Qb4. However, it loses miserably to 38.Rxb7+. Changing the move order yields 36... Qb4: A) ...
 
   Apr-22-14 E Prandstetter vs Hort, 1984 (replies)
 
agb2002: Black has a bishop and a pawn for a knight. If the rook on f1 were on, say, a1 then Black would force mate in two with 26... Nxf3+. Hence, 26... Bg1+ 27.Rxg1 (27.Kh1 Rxh3#) 27... Nxf3+ 28.Kh1 Rxh3#.
 
   Apr-21-14 Alatortsev vs Koblents, 1945 (replies)
 
agb2002: Black is one pawn ahead. White is about to bring the queen to the defense of the king. Pattern recognition finds a mate in two: 25... Rh1+ 26.Bxh1 Qh2#.
 
   Apr-20-14 D Fridman vs Naiditsch, 2013 (replies)
 
agb2002: The material is identical. White apparently tries to get rid of the knight on d4. The maneuver 21... Ndf3+ 22.gxf3 (22.Kh1 Qf6 - +) 22... Qd7, with the double threat Nxf3+ followed by Qh3 and Rf6-h6 followed by Qh3, looks promising: A) 23.Be2 Rf6 A.1) 24.Nd5 Rh6 followed by ... ...
 
   Apr-19-14 Macieja vs H Kallio, 1999 (replies)
 
agb2002: Black is one pawn ahead. White threatens 21.K(Q)xa2 and 21.Qxd7+. The first threat and the position of White's heavy pieces suggests 20... Rxe2, protecting momentarily the knight and unblocking the a1-h8 diagonal: A) 21.Bxe2 Nc3+ A.1) 22.Ka1 Nxd1+ 23.Kb1(a2) Rxe2 24.Rxd1 (24.Qxe2
 
   Apr-18-14 J Sieglen vs K Wesseln, 1989 (replies)
 
agb2002: Black is one pawn down. The black king is under check. The obvious move is 31... Rxf5, weakening the light squares around the white king, 32.exf5 Bd5+ 33.Bg2 Qh3: A) 34.Bxd5 f1=Q+ 35.Qxf1 Qxf1#. B) 34.Qf1 Qxg2+ (or 34... Bxg2 35.Qxg2 f1=Q+ 36.Qxf1 Qxf1#) 35.Qxg2 f1=Q(R)#. C) ...
 
   Apr-17-14 V Nielsen vs C F Delcomyn, 1894 (replies)
 
agb2002: White has the bishop pair for two knights and four pawns. Black threatens 25... Nd2+. The pawn on f5 protects both knights. This suggests 25.Rxg4 or 25.Rxf5. In the case of 25.Rxg4: A) 25... fxg4 26.Bxf7+ A.1) 26... Kf8 27.Bxe8+ Kxe8 28.Qxe4 gxh3 29.e6 d5 30.Qh7 looks winning. ...
 
   Apr-16-14 L T Haller vs Robbins, 1884 (replies)
 
agb2002: Black is one pawn down. White threatens 31.Qxe5. Black has four pieces and one pawn to attack the black king. This suggests 30... Rxh2+ 31.Kxh2 Qxg3+ 32.Kh1 Qh4+ 33.Qh3 (33.Kg2 Rg3#) 33... Rxh3+ 34.Bxh3 (34.Kg2 Q(R)g3#) 34... Qxh3#.
 
(replies) indicates a reply to the comment.

Calculo, luego existo

Kibitzer's Corner
< Earlier Kibitzing  · PAGE 7 OF 7 ·  Later Kibitzing>
Dec-26-11  CHESSTTCAMPS: <I also tried to guess the opening from which the position came, to accumulate some knowledge about what tactics one can expect from what openings but I forgot that habit.>

Another good idea, which I may pursue at least occasionally.

<If you want to impress your friends you should consider three Spanish products:...>

All of these suggestions sound wonderful, but I'm keeping to a fairly tight budget right now. Boxes of about 20 clementines sometimes sell for as low as $3.99 at Giant food stores, a terrific bargain. Later in the season, when the quality is not so good, the price sometimes rises to $10 or more - go figure.

I hope that you and your family enjoyed a wonderful Christmas.

Jan-01-12  CHESSTTCAMPS: <Yes, we experience similar price increases here. ...>

I take note of your point about Morroccan fruit being held to lower standards. Giant Foods has carried both Spanish and Morroccan clementines in recent years, the latter usually starting in January and later. Usually, both are delicious. I think that Giant is a reputable outfit and they would take care that their label means what it says. In any case, if there are serious doubts about the source, I think that consumer watchdogs would raise the issue loudly and clearly.

<Similarly, avoid some Italian "products",....>

This is interesting, something I was not aware of. I am a regular consumer of olive oil.

<Thank you, I wish you the same for you and your family and a good New Year.>

Thanks, Happy New Year to you, too.

Feb-03-12
Premium Chessgames Member
  Patriot: <agb2002> <Hello Patriot, how is the new year treating you? Hope everything is ok with you and your family.> My apologies for not responding to you sooner! I really thought I had responded back and just noticed I haven't!

Everything is going well with me and my family. I appreciate you asking and I hope all is well with you! Keep up the amazing work on the puzzles! Take care.

Apr-10-12
Premium Chessgames Member
  johnlspouge: Hola, <Antonio>.

Thanks for "dropping by". I hope you and your family are well.

I looked at the reviews of Penrose's "The Road to Reality", which I have not read, and I am daunted. Do I want to spend the time and effort required to understand the book?

I therefore turn your question back to you: what did you think of the book?

Be judicious in your answer, please ;>)

All the best,
John

Apr-12-12
Premium Chessgames Member
  johnlspouge: Hi, Antonio.

Your review link http://www.ams.org/notices/200606/r... was good enough. The book is a must-read. I will let you know how it goes.

Thanks for thinking of me :)

All the best,
John

Apr-15-12  quantum.conscious: hi <antonio> , thanks for your posts about roger penrose books. i found them very interesting.
Apr-17-12
Premium Chessgames Member
  agb2002: <quantum.conscious: hi <antonio> , thanks for your posts about roger penrose books. i found them very interesting.>

Thank you! It seems that the interest on Penrose's Road is skyrocketing: I can count three now which means a tremendous increase of 50%! ;-)

May-11-12
Premium Chessgames Member
  ketchuplover: Go Boris!!!!!!!
Jun-11-12  LoveThatJoker: <agb2002> Hi! I'm sending you this note to firstly thank you for your kind and objective acknowledgment on M Beinoras vs H Salo, 2009. I made sure to post my original thank you there!

I had a fellow CG full member, <AlienMath> post a question on High-Mathematics on my forum that I cannot assist on elucidating on, due to the fact that I am not a trained Mathematician.

The question is located directly on this link LoveThatJoker chessforum.

Any help on the elucidation of the concepts of both the Goldberg conjecture and the Riemann hypothesis would be genuinely appreciated.

Thank you!

LTJ

Jun-12-12  LoveThatJoker: <agb2002> Thank you for the kind reply on my forum!

LTJ

Jun-14-12  LoveThatJoker: <agb2002> Do you have any idea who this is?

Look at Book 3 here http://chessbase.com/newsdetail.asp....

I will give you anyone you want in exchange for this one.

LTJ

Jun-15-12  LoveThatJoker: <agb2002> Thank you for getting back to me on that!

LTJ

Jul-22-12
Premium Chessgames Member
  Patriot: Hi <agb2002>! <I agree. I still have to rethink my move selection algorithm.> Usually you latch right on to the correct move. Do you consider other candidates or do you usually only post the principle candidate after analysis? For example in today's puzzle, I thought 22.Bh6 was a good candidate and 22.Nb5 was interesting, although I didn't post anything about it initially. 22.Rxf6 was the first move I saw but I didn't see the Kh1, Rg1 idea and thought it was unnecessarily complicated.

By the way, good job on the POTD!

Oct-01-12
Premium Chessgames Member
  morfishine: Hello <abg2002>! Nice write-up in the Sunday POTD! I only noticed <25...Bxe4> immediately after posting 25.Rxb4 <25...axb4>. I briefly considered deleting my post then adding this as a possible improvement but decided to leave these separate.

I'm a bit surprised there wasn't more discussion on <25...Bxe4>

Nov-14-12
Premium Chessgames Member
  Patriot: Hi <agb2002>! Good job on your win! I read your comment about losing the exchange before going over your game so when you played 20.Rae1 I figured the rook on f1 was going to be *the* piece. I've lost the exchange quite a few times like this so I'm very suspicious about moves that trap the rook.

I had a question about 11.Nxe7+. What prompted you to play this? That knight is a real thorn thanks to 9...b6?. I wouldn't recommend trading it until forced to do so since the bishop isn't going anywhere. That's similar to what Dan told me once when I captured a pinned piece. He said "You should almost never capture unless they threaten to break the pin or capture the pinning piece, for example." By not capturing, you have time to build your position further while he is left dealing with the situation.

It really looks like you did have a bad day though--we all have them! I just thought I'd mention the knight capture though because that move really stood out with me. But it's probably something you wouldn't have done on any other day!

Thanks for sharing!

Nov-25-12  ShahMaat: ...no comment.New guy on the block.I enjoy the dialogue between the users.I thank you all,and look forward to crossing swords with you!Unrated old fart.
Jan-18-13
Premium Chessgames Member
  Patriot: Hi <agb2002>! I loaded your game into Fritz and followed it. You played a nice game against Houdini! On move 35 (white to play), how did you evaluate the position:


click for larger view

I might think black is a little better, and Houdini agrees after 22-ply. You said 35.Bf1 was better but at 22-ply, it agrees with you! <35.Ba6>

Jan-19-13
Premium Chessgames Member
  Patriot: Hi <agb2002>! <Perhaps the note below the players showing the engine which performed the analysis misled you.> Yes this is exactly what happened--I completely misread that (sorry).

Your plan, having the outside passed pawn, is a good one. Nice game!

Mar-03-13
Premium Chessgames Member
  Jimfromprovidence: Thanks for the constructive feedback concerning Saturday's puzzle.

Jim

Nov-01-13
Premium Chessgames Member
  Patriot: <<agb2002>: <Patriot: <agb2002> <Pattern recognition finds the mate scheme...Therefore...> If the pattern led you to the sequence, I'm impressed. I had to work out a sequence before visualizing the position as a win.> You surely have already noticed that in competition chess you never have enough 'stored' patterns.> Oh definitely! I don't doubt that you solved it this way, but it struck me oddly because I have listened to NM Dan Heisman analyze <CG> problems that I gave him, "live". And I'm quite certain he would not have worked backwards from the pattern you illustrated. And I don't think, even knowing the pattern, I would ever be able to link the pattern to the problem and solve it backwards. That's one heck of a skill!
Nov-03-13
Premium Chessgames Member
  agb2002: <Patriot>

Thank you! The way you describe the solving process reminds me of Raymond Smullyan logic puzzles in his "The Chess Mysteries of Sherlock Holmes".

Dec-04-13  LoveThatJoker: <Dear CG Friends>

I know this is irregular, but I am stepping outside of the box, for you to view truly one of the most exciting alternate solutions ever posted on the daily puzzle:

G Weissgerber vs A Van Nuess, 1933

With friendship, respect and gratitude for your time in looking at this,

LTJ

Mar-05-14
Premium Chessgames Member
  LIFE Master AJ: Hello:

Game Collection: "Chess-Games" >Problem of The Day< (2014)

I am trying to update a collection ... with all the puzzle for this year.

Have you missed any days this year ... that you know of? If so, could you help me to locate the missing days?

Mar-06-14
Premium Chessgames Member
  LIFE Master AJ: << Hello LMAJ, according to CG I have posted (or perpetrated) an analysis every day this year with the sole exception of Feb 17th (I don't remember what happened that day). If I can help you just let me know. >>

Cool! Then I will be looking through your posts and trying to update my collection. (I am glad that you don't mind.)

Think you could ask any of your friends and find out what the POTD for Feb. 17th was? (Ask them to leave a comment in my forum.)

Mar-08-14
Premium Chessgames Member
  LIFE Master AJ: S Williams vs The World, 2013

Weren't you a big-time member of the team?

Jump to page #    (enter # from 1 to 7)
< Earlier Kibitzing  · PAGE 7 OF 7 ·  Later Kibitzing>

A free online game for all chessgames members!
NOTE: You need to pick a username and password to post a reply. Getting your account takes less than a minute, totally anonymous, and 100% free--plus, it entitles you to features otherwise unavailable. Pick your username now and join the chessgames community!
If you already have an account, you should login now.
Please observe our posting guidelines:
  1. No obscene, racist, sexist, or profane language.
  2. No spamming, advertising, or duplicating posts.
  3. No personal attacks against other users.
  4. Nothing in violation of United States law.
Blow the Whistle See something that violates our rules? Blow the whistle and inform an administrator.


NOTE: Keep all discussion on the topic of this page. This forum is for this specific user and nothing else. If you want to discuss chess in general, or this site, you might try the Kibitzer's Café.
Messages posted by Chessgames members do not necessarily represent the views of Chessgames.com, its employees, or sponsors.

You are not logged in to chessgames.com.
If you need an account, register now;
it's quick, anonymous, and free!
If you already have an account, click here to sign-in.

View another user profile:
  


home | about | login | logout | F.A.Q. | your profile | preferences | Premium Membership | Kibitzer's Café | Biographer's Bistro | new kibitzing | chessforums | Tournament Index | Player Directory | World Chess Championships | Opening Explorer | Guess the Move | Game Collections | ChessBookie Game | Chessgames Challenge | Little ChessPartner | privacy notice | contact us
Copyright 2001-2014, Chessgames Services LLC
Web design & database development by 20/20 Technologies