December 31, 2008

Checkmate in 5

Originally posted by SusanPolgar here: Checkmate in 5

December 29, 2008

Checkmate in 7

Here is the link to the actual game Robert James Fischer vs William Hook
Originally posted by SusanPolgar here: Checkmate in 7

Checkmate in 9

Originally posted by SusanPolgar here: Checkmate in 10

December 28, 2008

Checkmate in 3

Originally posted by SusanPolgar here: Checkmate in 3

December 27, 2008

World Champion's Tactic

Here is the link to the actual game Predrag Nikolic vs Viswanathan Anand
Originally posted by SusanPolgar here: World Champion's Tactic

Kasimdzhanov 1-0 Cheparinov (Elista GP)

Test your checkmating skill

White to move and checkmate in 4. Originally posted by SusanPolgar here: Test your checkmating skill

December 26, 2008

Checkmate in 4

Originally posted by SusanPolgar here: Checkmate in 4

December 24, 2008

December 24 checkmate tactic

Originally posted by SusanPolgar here: December 24 checkmate tactic

December 22, 2008

Cheparinov 1-0 Alekseev in Elista

Monday morning tactic

Originally posted by SusanPolgar here: Monday morning tactic

Handling illegal moves

It seems obvious that illegal moves are just that (illegal) and we shouldn’t worry about them.
For example, the PGN specification (section 8.2) is very clear saying:

PGN specification quote: "Because illegal moves are not real chess moves, they are not permitted in PGN movetext. They may appear in commentary, however. One would hope that illegal moves are relatively rare in games worthy of recording."

In other words an illegal move is not permitted at all and can invalidate the whole PGN. I’m not going to question what the PGN specification found impossible to solve. They stayed focused on chess and they did a pretty good job doing it.

Unfortunately, there are examples of actual games where illegal moves were played. One of those was pointed out by MostlyAverageJoe (on chessgames.com): Wolfgang Heidenfeld vs. Kerin
(Note: As of 21-Oct-2009 the link doesn’t work anymore and the game is not available at CG.com – most probably deleted!)

The funny problem is that in this game white castled twice. White’s move 33.0-0-0 is illegal and any PGN complaint viewer will either ignore it or (much better) show it as illegal.

Fortunately, in this particular case PGN allows an elegant workaround as follows. I moved out the illegal section of the game into its own game (“Part: II”). It shows all the moves starting at white’s 33.0-0-0 and we can enjoy the rest of the game the way it was actually played.

UPDATE: A very recent example of handling a similar situation in an official tournament is the following game. I’m glad my understanding above is in unison with the way the game is presented in the provided PGN and on the official site (using ChessTheatre software).

Checkmate tactic

Originally posted by SusanPolgar here: Checkmate tactic

December 20, 2008

Round 9 in Nanjing

Saturday morning tactic

Originally posted by SusanPolgar here: Saturday morning tactic

December 19, 2008

Are you smarter than a WC? (#2)

Anand also "missed" a checkmate in 4 in this game Viswanathan Anand vs. Fritz (Computer) in the following position.

Round 8 in Nanjing

December 18, 2008

Are you smarter than a WC?

Here is the link to the actual game Vladimir Kramnik vs Garry Kasparov

Notice that both players have ratings above 2800 mark. Kasparov’s 2838 is impressive even in today’s “money” and he is not too far from his peak of 2851 which he had the previous year (during Corus 2000).

Here is something else you might find interesting. According to my engine the move 49… Bg3+, which Kasparov played, is “mate is 7”. Usually in such positions GMs resign saving themselves the embarrassment. Why was Mr. Kramnik playing on? I don’t think he was hoping for a miracle. Can we assume that he also missed the mate?

Originally posted by SusanPolgar here: Are you smarter than a WC?

December 17, 2008

Round 6 in Nanjing

Originally posted by SusanPolgar here: Topalov 1-0 Aronian in Nanjing and Bu 1-0 Movsesian in Nanjing

December 16, 2008

Nanjng chess tactic

Originally posted by SusanPolgar here: Nanjng chess tactic

December 15, 2008

Topalov vs. Svidler

Originally posted by SusanPolgar here: Topalov 1-0 Svidler in Nanjing

December 12, 2008

Real game tactic

Originally posted by SusanPolgar here: Real game tactic

December 11, 2008

Sharp tactic

Originally posted by Admin here: Sharp tactic

Mate in three

The above was originally posted by Admin here: Thursday morning chess tactic

Sure, Mr. Rodshtein (white) didn’t miss the mate and his opponent (Mr. Caspi) resigned after Rxg8+. Two moves earlier in the game though, in the following position, a very nice tactics could've been played.
Can you find it?

December 10, 2008

Some traps in the Sicilian game

This was originally posted by Chess Teacher here: Some traps in the Sicilian game. (In a recent update, dated April 2010, the author prepended an unfortunate note starting with “The method stopped working and the post has been replaced by some images …”.)

I’m re-posting it as a comparison of different publishing methods. I hope to get some feedback about the advantages and disadvantages of each approach from the end-user‘s point of view. For example, how easy and intuitive can we navigate through variations?

Early morning chess tactic

Originally posted by SusanPolgar here: Early morning chess tactic

December 7, 2008

Sunday morning classic

Originally posted by SusanPolgar here: Sunday morning classic

December 5, 2008

Checkmate tactic

Originally posted by SusanPolgar here: Checkmate tactic

December 3, 2008

Wednesday morning tactic

Originally posted by SusanPolgar here: Wednesday morning tactic

December 2, 2008

Using the Chess Viewer Applet

This is a demonstration of some custom features:
  • Dark squares have a different color;
  • Second game is pre-selected;
  • The viewer is enclosed in a bordered box;

Here is the modified CV section of the post body that is producing these results:

<div style="border: 1px solid blue; width: 651px; height: 580px;">
<script id="oChessViewer" style="margin: 10px;" type="text/javascript">
/*
[Event "Munich"]
[Site "Munich"]
[Date "1991.??.??"]
[Round "?"]
.
.
.
1-0
*/
makeChessApplet ( null, { DarkSquares: "C08262", GameToSelect: "2" } );
</script>
</div>

Below are the actual changes along with some explanations and internal processing details:

  • The way new parameters are submitted to the Chess Viewer Deluxe applet. Proper values are assigned to two of them (“DarkSquares“ and “GameToSelect“) which are passed in when the “makeChessApplet” function is called. The most common parameters are handled nicely by the “HTML generator” so you don’t have to do it manually (but you could). For a complete list of all possible parameters check the CVD’s home page.
  • There is a mandatory ID of “oChessViewer” defined on the SCRIPT element. The ID is later inherited by the chess viewer (CV) object. That's quite convenient and can be used in your CSS (as I do in mine) to define a style that applies to each of the CV objects.
  • There is an optional “style” attribute defined on the SCRIPT element which also gets inherited by the CV object. The example makes good use of it to overwrite the current settings for margins (from the CSS).
  • The outer box is defined in the most usual HTML fashion and shows how easy the CV object is nested inside it. In fact, the CV object literally replaces the SCRIPT element and, from user’s point of view, the PGN data is naturally inherited by it.

Jana Jackova vs. Anatoly Karpov