Friday, 24 November 2017

Greedy Santa

With Christmas approaching, there will be a lot of work parties and opportunities for gift giving. I've already had one such get together, and at this I was introduced to "White Elephant Secret Santa", which is an alternative to the basic 'Secret Santa' that most people know about.
This got me thinking about a 'Game Theory' version of the game, and what the 'best' strategies are.
Firstly some rules:

  1. There are N players
  2. Each players pays N/2 dollars to take part
  3. N envelopes are filled with an amount of money starting with $0, then $1 up to $N-1
  4. Each player takes a number at random, lowest number choosing and opening the first envelope, revealing the money inside.
  5. Subsequent players (starting at 2) can either steal money from another player, or chose to open a sealed envelope.
  6. If a player has money stolen from them, they then get the same option (steal or open). Once a player opens an envelope, this turn ends and a new one starts with the next player
  7. An amount can only be stolen once per turn, and there is a limit on the number of times an amount can be stolen overall (usually the third owner keeps it for good).

The addition of Rule 7 adds an extra level of strategy, as trying to steal the largest amount runs the risk of having it 'frozen' by another player. On the other hand, the last player may have the most power, as they have the greatest choice of what to take (and essentially a retaliation proof grab).
I don't know if anyone has done the maths on this, but it looks as though it may be an interesting programming exercise, both to simulate the game, and to try and generate the best strategy.


Thursday, 23 November 2017

2017 World Junior

Two notable stories are coming out of the 2017 World Junior, which is currently being held in Italy. Firstly R Praggnanandhaa is on track to become a GM at the age of 12, although he does need to finish 1st to gain it automatically. After 9 rounds he is in third place, half a point of the lead, and has already earned a GM norm (with a 2700+ TPR).
Secondly, Australian representative Kevin Willathgamuwa is performing well over his pre tournament rating (1996), with a 2300 TPR. He was on 50% after 7 rounds, and although he has fallen back a bit, he is still gaining over 100 rating points, having played 8 IM's in his first 9 games. His brother Rowan is also playing in the tournament and is also picking up points, reaching 3/9.
There are 2 rounds left to play in this tournament, and the results (plus some games) can be found at chess-results.com

Wednesday, 22 November 2017

Slim pickings

Unlike round robins, swisses are normally a feast of good and bad chess, where every game is important (except maybe the last round), and players bounce up and down the standings with great regularity. Unless of course it is an elite swiss, in which case, every treads warily, keeping a close eye on all the games to make sure no one is getting too far ahead.
The Mallorca Grand Prix is providing slim pickings for anyone who likes the score table to contain lots of 1's an 0's. Not to disparage a good hard fought draw, but with over 60% of the games ending that way, not every draw is a result of players battling till exhaustion.
Of the decisive games, there have been a few that have jumped out at me. The one I've chosen for this post was Svidler's win over Hammer. Apart from the rarity of seeing 'actual mate on the physical chessboard', the fact the White king gets hacked on the kingside in a sicilian also adds to its attractiveness.


Hammer,Jon Ludvig (2629) - Svidler,Peter (2763) [B51]
Palma De Mallorca GP 2017 Palma de Mallorca ESP (3.5), 18.11.2017



Monday, 20 November 2017

Happy Birthday Capa

Toady is the 129th anniversary of the birth of Jose Raul Capablanca. Generally considered one of the "Top 5" World Champions (along with Alekhine, Fischer, Karpov and Kasparov) he started as a child prodigy, before  become a full time player at the age of 20. He won the World Championship in 1921 and then lost it to Alekhine in 1927. He never had another chance to play for the title, and died at the relatively young age of 53.
Capablanca was considered a positional player, focusing on piece placement, and improving his position through 'petite combinations'. This enable him to outplay his contemporaries, although he met his match against Alexander Alekhine. His style influenced the next generation of chess players, especially Bobby Fischer and Anatoly Karpov.
Even at the end of his career he was still able to target a weakness and build an entire game around it. In the game below (his final tournament game), he isolates Black's c pawn on move 9 and then builds up pressure on it. Black is forced to make positional concessions to defend it, and eventually ends up in a lost position.


Capablanca,Jose Raul - Trompowsky,Octavio [E01]
Buenos Aires ol (Men) fin-A Buenos Aires (15), 18.09.1939



Saturday, 18 November 2017

Chess and Beer

Due to a number of other activities I haven't been running Street Chess recently. Today was my first time back since the start of October, and on my return, I received a pleasant reward.
One of the event sponsors, King O'Malley's Bar, was running a 'design your own beer label' promotion, in conjunction with Adobe. This was too good an opportunity to pass up, so I created a very limited run of "Street Chess Beer". So limited that only 4 bottles were made. Three were given away as prizes(although not to the tournament winner Sankeertan Badrinarayan as he isn't quite 18), and one I kept myself (although I only have the bottle, as my 19 year old son consumed the contents).
A couple of people wondered If i had brewed the beer myself (No), but maybe this is something worth looking at in the future.
"Drink & play responsibly"

Thursday, 16 November 2017

FIDE Grand Prix resumes

The final event of the 2017 FIDE Grand Prix series begins today in Mallorca, Spain. While the GP series tends to get lost among the other big events on the calendar (GCT, World Cup plus big opens in Iceland, UK and Isle of Man), it still helps determine the qualifiers for next years Candidates Tournament. The top two finishers (who did not qualify through the World Cup) qualify for the Candidates, and at this stage there are 4 players still in with a chance. 
Mamedyarov and Grischuk currently hold down the top two places, but have already played there 3 events (each player plays 3 of the 4 GP tournaments). As a result, there is still a chance they can be overtaken by Vachier-Lagrave and Radjabov. Ding Liren is also in the leading group but has already qualified (via the World Cup).
The official site for the tournament is https://worldchess.com/gp2017/ I'm pretty sure there is no free coverage from this site (it is a pay for view event), and I'm not seeing any of the other major websites with links to coverage (although I may have missed them). Whether this is due to legal reasons or indifference (or indifference caused by legal reasons) I do not know.

Wednesday, 15 November 2017

The injustice of it all

While wearing my ICCF Tournament Directors hat, I discovered something I had not previously been aware of. There are some Queen endings where two connected passed pawns aren't enough to win. This was drawn to my attention when a game in an event I was directing was drawn after one of the players made a tablebase claim (In Correspondence Chess a player can claim a draw or win if the position is assessed as such in a 6 piece or less tablebase). While the claim was perfectly valid I did feel a little sorry for the other player involved.
Even without the advantage of modern technology, the game may well have been drawn anyway, as it turns out there have been some precedents.  In 1985 Boris Spassky was defending exactly the same position against Zoltan Ribli and successfully held. Here is the game in question, with Black having a completely drawn potion by move 82.


Ribli,Zoltan (2605) - Spassky,Boris V (2590) [A30]
Candidates Tournament Montpellier (4), 1985