29 December 2012

Top Posts of All Time

As a year-end post on each of my three blogs, I had intended to highlight the top-10 most popular posts of the year for that blog. It turns out that the Blogspot.com toolset doesn't return statistics for the past year. They are available only for the past day, week, and month, or for 'all time'. For 'all time' it will be.

First, here's a chart showing monthly traffic since this chess960 blog started in May 2009. That peak near the middle, followed by the steep drop, is June 2010. Since then, the trend has been mostly 'up'.

Second, here's a list of the top-10 most popular posts of all time. A post introducing a list of online play sites heads the list, followed by two posts centered on Fischer himself.

It might be useful to look at keywords used on searches that found the blog, but the toolset no longer provides those statistics.

22 December 2012

The Lechenicher SchachServer

Since I was first bitten by the chess960 bug -- Shall We Play Fischerandom Chess? -- I've been playing chess960 primarily on Scheming Mind. It's a great site with first class management and I have only good things to say about it. The site offers several formats of which my favorites are the league and dropout competitions, both involving two simultaneous games per round with rounds starting at intervals of several months. For me, it's the right balance of chess960 to go with my other responsibilities.

For the 2013 Chess960 Dropout tournament, the site announced a change of format.

Please note that for this tournament, we are trying a new "Countdown" time control. Under countdown time, each player is allocated a fixed time at the beginning of the game (in this case sixty days) - this time is for the entire game, no increments will be added and holiday will not be applied to these games.

Even though the countdown time control is intriguing, I decided that it might be too demanding on my time budget, especially since my games against good players often go into the endgame. How would I pace myself over 60 days, not knowing how many moves the games would last? There was also the issue of no vacation. I tend to minimize online access while on vacation and I'm certain my wife would not be happy if I spent too much vacation time at a chess board. Signing up for the tournament meant up to six rounds with two games per round, plus a high risk that I would eventually crash & burn for lack of time.

While wondering whether to join or not, I remembered that the Lechenicher SchachServer (LSS) also offers the countdown time control, its only format for playing chess960. I had hesitated to play there partly because of the question of unknown game length and partly because I had enough games on Scheming Mind (SM) to keep me busy. The LSS countdown control is 90 moves for the game with 14 days of vacation, more relaxed than the SM equivalent. The five-player double round robin means eight games starting at the same time, but I can time my participation to coincide with those times of the year when I have less to do.

The upshot of this is that I started to play my first chess960 tournament on LSS and hope to report on the site's chess960 culture from time to time. I also started a new tag category to collect the posts; see 'Labels' in the right navigation bar. One other post deserves to be linked because of a long comment that mentions LSS:-

After gaining countdown experience on LSS, I can always return to SM to try the faster control.

15 December 2012

An Attack Is Playing to Lose?

In my previous post, Initial Pawn Moves and Castling, I found the graphic technique useful to understand the difference between the twins I discussed. It was so useful that I returned to the post before that, Twin Research, to identify the next pair of twins on that particular list.

The second pair of twins exhibiting widely varying success rates for White and Black were SP301 QNRBKRBN and SP376 NBRKBRNQ. The position SP301 had an average success rate for White (%W) of 47.0%, while SP376 had %W of 62.9. That means SP301 was more successful for Black, and SP376 more successful for White.

The following chart shows the two SPs next to the results collected from the CCRL's engine vs. engine data (once again, see the sidebar for a link to the CCRL data). For example, the data for SP301 says that the most popular move, 1.Ng3, was played in 89 games and had a 43.2% success rate for White (%W again). The second most popular move was only played in 14 games. I haven't listed the other first moves given by the CCRL for that SP, all of which were seen in less than 10 games. The second block of stats for SP301 shows all of the responses to 1.Ng3. The move 1...f6 was played in 47 of the 89 games and was largely responsible for the low %W.

The data for SP376 tells a different story. While 1.Nb3 (the logical counterpart of SP301's 1.Ng3) was again the most popular first move, the response 1...c6 (the counterpart to SP301's 1...f6) is further down the list. The top response to 1.Nb3 was 1...Nb6, a move whose SP301 counterpart 1...Ng6 is nowhere to be found. What's going on here?

As luck would have it, I've already discussed this pair of twins in another post: Watch out for ****KRBN. In SP301, after 1.Ng3, White is threatening a dangerous attack on g7. The most common opening sequence on CCRL was 1.Ng3 (x89 moves) f6 (x47) 2.f4 (x34) Ng6 (x19). Now there were three moves (total x22 due to transpositions), all played about the same number of times, and all with %W less than 50%. The worst of the three moves was 3.Nf5 with a score of +1-6=0, i.e. a disaster for White.

In SP376, after 1.Nb3 there is no attack on b7 because of the option to castle ...O-O-O. The most common opening sequence was 1.Nb3 (x88) Nb6 (x38) 2.c4 (x21), and now there were two moves more popular than 2...O-O-O (where White won all games). The first move was 2...g6, where the score was +1-7=0; the second was 2...Na4, with a score of +5-1=0. These scores, both disasters for different sides, make no sense to me. Perhaps they can best be explained by the small number of games played.

In both SPs, it appears that the side playing for the attack is 'playing to lose', as the old chess saying goes. I would love to investigate this further, but I'm afraid I've run out of time.

08 December 2012

Initial Pawn Moves and Castling

In Twin Research, I looked at data from CCRL engine vs. engine competition where the chess960 start positions (SPs) were twins, i.e. SPs with the pieces in reverse order relative to each other. One of the discoveries was a list of five pairs of twins having the highest difference in average success rate, i.e. one of the twins has a good score for White, while the other has a good score for Black. For example,
SP222 NQRKNBBR has [an average success rate for White (%W)] of only 43.3%, while its twin, SP644 RBBNKRQN, has %W of 59.8%.

Is this a statistical fluke or is there an underlying reason? I noted,

Four of the five twins with the largest difference in %W have one SP in the pair where castling is possible on the first move. This indicates that the ability to castle quickly is an important defensive strategy in a difficult position.

After posting those observations, I noticed that the four pairs of twins didn't support my conclusion. Where castling was possible on the first move, White had a significantly better score in two of the pairs, while Black was better in the other two. I decided to take a closer look at the twins from my example, SP222 and SP644.

The following table shows some basic information for the two SPs. The column on the right shows the most frequent first moves for each SP along with each move's score for White. For example, in SP222 the move 1.Nb3 was played 35 times and scored 42.8% for White; in SP644 the equivalent move 1.Ng3 was played 36 times and scored 48.6% for White. The two Knight moves appear to affect their respective SPs in the same way.

I doubt that the difference between SP222's 1.Nb3 score of 42.8% and SP644's 1.Ng3 score of 48.6% is statistically significant. A more promising investigation would be SP222's 1.c4 score of 35.7% and SP644's 1.f4 score of 61.2%. Both first moves involve pushing the Pawn in front of a Rook. It so happens that the chosen Pawn is relevant to the position of the castled King on that side.

In SP222, the move 1.c4 weakens an eventual O-O-O; in SP644, the move 1.f4 makes space for the Rook after an eventual O-O. Is that the reason for the difference in scores for White? More investigation is required to answer that question.

01 December 2012

Twin Research

In my previous post, Waving a Yellow Flag, I identified five chess960 start positions (SPs) having the highest success rate for White in play between engines. HarryO proposed to play a few games using those SPs in order to gain some insight into the reason for White's success. Since there are no online play sites that let opponents choose a specific SP, we are playing via comments on his blog, with the first game being conducted in the post Non-Random Chess 960 Trial Game 6: SP408.

Two of those five SPs were twins, positions with the pieces in reverse order relative to each other. Twins have similar characteristics for early piece development and tactics -- only different castling options distinguish them -- and early problems for Black in one twin could easily occur in the other twin. I decided it would be useful to identify other pairs of twins with high success rates for White, so I returned to the data described in the 'Yellow Flag' post to find more.

The following table shows the five twins with the highest average success rate for White (%W AVG). SP408 and its twin head the list, since they were the twins that I had already identified (the lower numbered SP is always listed in the left column). The traditional start position, SP518, and its twin are given as a reference point. The next five entries in the table are the twins with the lowest average success rate for White. If there are any start characteristics that favor Black, they might be hidden in these SPs.

At the bottom of the table are five twins with the highest difference in %W. For example, the first entry SP222 NQRKNBBR has a success rate (%W) of only 43.3%, while its twin, SP644 RBBNKRQN, has %W of 59.8%. The difference between the two values for %W is -16.5. It is of no importance that the lower numbered SP or the higher is more successful; only the absolute value of the difference is important.

Four of the five twins with the largest difference in %W have one SP in the pair where castling is possible on the first move. This indicates that the ability to castle quickly is an important defensive strategy in a difficult position. The only exception to the possibility of early castling is the third pair of twins, SP424 RBNQBNKR and SP733 RKNBQNBR. Why do these twins have such a large difference in success rate for White?

There are plenty of avenues for further investigation here, and I hope that HarryO and I will find the time to tackle a few of them. If so, I'll report on our discoveries in future posts.