29 September 2020

Splitting a Gold Medal

Last month's summary of mainstream chess news, Top News / Tournaments in August (August 2020), included this small item:-

I identified the top five events in each weekly edition of Mark Crowther's 'The Week in Chess' (TWIC). [...] It's curious that the Olympiad received top-five billing only once in August. In TWIC 1346 ['24th August 2020'] it was listed at no.21 out of 23 events.

If I had waited a few more days, I could have cherry picked dozens of Olympiad stories from major news sources, all similar to the following.

I also spotted a segment on BBC World News. It was subsequently captured for Youtube's channel, FIDE chess.

BBC reports on the Online Chess Olympiad (3:15) • '[Published on] Aug 31, 2020'

The piece included a discussion with a behind-the-scenes insider:-

Nick Barton, Director of eSports and Events at Chess.com, who together with the International Chess Federation [FIDE] set up the Olympiad. He's in Houston, Texas.

For the accompanying BBC story, see:-

The story coontinued,

An online version of the Chess Olympiad contest is being held for the first time this year because of coronavirus. India appealed after two of its players lost connection to their games and forfeited on time.

The FIDE decision to declare joint winners, made by FIDE President Arkady Dvorkovich, was roundly criticized on all sides. A few days earlier the event had incurred another blow when Armenia, in a match against India, lost a game on a server disconnect. Armenia withdrew from the event in protest.

28 September 2020

TCEC S19 Preparing Sufi; CCC15 Still Halted

Two weeks ago, in the previous report on two long-running series of engine vs. engine competitions, I noted 'this post might turn out to be one of the shortest in the series'. To summarize that post, TCEC S19 DivP Chugging Along; CCC15 Halted (September 2020), making it even shorter:-

TCEC: The Premier Division (DivP) has reached the fifth of eight all-play-all rounds. • CCC: Because of technical problems, the CCC15 'Round 2' matches were halted about half way through. The site is currently running a series of CPU-only exhibition events.

This current post promises to be equally short.

TCEC: DivP is the equivalent of the Candidates tournament in the FIDE World Championship cycle. It finished with the results shown in the following crosstable.

Stockfish and LCZero finished 1st/2nd to qualify into the S19 final match (aka Superfinal, aka Sufi). Stockfish won the eight-game mini-matches against all seven of the other competitors, including a +1-0=7 score against LCZero, losing only one game, to Komodo, along the way. LCZero was +5-1=1 in mini-match play, drawing the match with third place Alliestein after all eight games were drawn.

The Sufi should start this week. TCEC planning says it will last about 17 days.

CCC: There is no news on the technical problems affecting the GPU engines.The only information on the site informs,

!next • Four rounds of CCRL Ratings Standardization, 200 games each.

For more about the the Computer Chess Rating Lists, see CCRL (chessdom.com). The CCC is currently conducting the second of the four rounds. I could find no explanation of what is meant by 'Ratings Standardization'. Since the matches involve two engines, I suppose the goal is to verify that the results of the 200-game matches are close to the expected score calculated by the CCRL rating difference between the two engines.

[For further information from the various stakeholders in the engine-to-engine events, see the tab 'TCEC/CCC Links' at the top of this page. • NB: Leela = LC0 = LCzero]

27 September 2020

Quantum Chess and AI

Soft science, meet hard science. Or, more specifically, Sociology of Chess (November 2016), meet Quantum Chess.

Introduction to Quantum Chess - Quantum Summer Symposium 2020 (13:53) • '[Published on] Sep 3, 2020'

The video is from Youtube's TensorFlow channel, which describes its subject as 'an open-source machine learning framework for everyone.' The video description says,

Megan Potoski, Chris Cantwell, and Doug Strain introduce Quantum Chess as a fun tool for quantum education. This presentation was recorded on Day 1 of Google's Quantum Summer Symposium 2020 (July 22, 2020).

The description also links to a Symposium 2020 video playlist. A few years ago, in a post titled Quantum Chess (February 2017), we saw one of the current presenters in a video titled 'Christopher Cantwell - Quantum Chess: Making Quantum Phenomena Accessible'. In the current video, Cantwell referrs several times to 'iswap'. A Google search on 'quantum iswap' leads to Quantum logic gate (wikipedia.org). The page starts,

In quantum computing and specifically the quantum circuit model of computation, a quantum logic gate (or simply quantum gate) is a basic quantum circuit operating on a small number of qubits. They are the building blocks of quantum circuits, like classical logic gates are for conventional digital circuits.

Although the Wikipedia page doesn't use the term 'iswap', Google sends us there anyway. Google knows everything about everything.

25 September 2020

A Cascade of Chess Variants

I ended last week's post, Nine Chess Variants, saying,

GM Kramnik's latest ideas might promise a wealth of new material related to AI/NN.

Before tackling that, I would like to finish reviewing a related video on Youtube's Chess.com channel.

DeepMind Roundtable with GM Vladimir Kramnik, IM Danny Rensch, and the DeepMind team (1:49:21) • 'Streamed live on Sep 18, 2020'

The description says,

Chess.com hosts a round-table discussion with GM Vladimir Kramnik, IM Danny Rensch and researchers of Deepmind discussing their latest paper in which AlphaZero explores chess variants.

During the past week, Chess.com also released software to play many of the variants: AlphaZero (And Other!) Chess Variants Now Available For Everyone.

Six new variants, including four from the recent AlphaZero paper, are now available for all Chess.com members to try.

The page includes brief explanations of the variants. Four endorsed by GM Kramnik -- No Castling, Capture Anything, Sideways Pawns, and Torpedo -- plus three others gives seven new variants, not six. Was 'No Castling' previously available? Kramnik introduced it in December 2019.

My priority objective would be to eliminate the usefulness of tablebases (TB). Some of the variants would require new TBs to be constructed, but I don't see any that would do away with TBs entirely -- maybe 'Fog of War'?

24 September 2020

2020 CJA Awards - Part 1 bis

After last week's post 2020 CJA Awards - Part 1, I had hoped to wrap up Part 2 today, but the CJA site is currently out of service. It displays the message shown below.

In Part 1, I quoted an email from the CJA that said,

Our webmaster has arranged for us to move to a site that will allow us many more options. [...] We will have the new website in a couple of weeks and this should allow us to make the awards much more available to the general public.

As for me, I decided,

Although the award announcements are accessible on a couple of other sites, I'll allow a little more time for the move to Chessjournalism.org.

The CJA site was formerly hosted on Wix.com, which is the source of the message shown above. The new host will be Weebly.com. A week ago, the future host was showing pages from the new site, including the 2020 CJA awards. Now it redirects to the same message from Wix.com. A DNS problem? To be continued...

22 September 2020

Chess Is Not a Sport!

But bowling is, at least according to more than 50% of respondents to a survey. Chess as a sport received a 14% rating from both men and women. In the most recent monthly featured video on this blog, A Fast Paced History of Chess (September 2020), I mentioned a statistics site I hadn't seen before and transcribed some commentary from the clip:-

The web site 'Statista' values the worldwide boardgaming industry at $7.5 billion. And it's not exactly a new thing -- the same web site values the industry around the game of chess, more than a millennium old, at around $190 million.

A search of the site using my favorite keyword returned 50 Statista chess search results. Along with questions like 'Share of adults in the U.S. that think chess is a game of chance' (you have to register with the site to find out), the most relevant was probably, 'Which of the following activities, when participated in competitively, would you consider to be a sport?'. Here is the chart returned in answer to the question.

Source: Activities considered to be a sport 2014 (statista.com)

Of the 13 activities listed on the chart, chess is 9th, behind billiards/pool, but ahead of poker, quidditch [NB: ?], video gaming, and competitive eating [NB: ??]. Several notes to the chart are particularly relevant:-

Release date: January 2015
Region: United States
Age group: 18 years and older
Special properties: All adults who enjoy watching sport

For more about the service, see Statista (wikipedia.org).

21 September 2020

Stockfish NNUE Dev

Six weeks ago, when I posted Stockfish NNUE = +90 Elo (August 2020), I wrote,

I hope some kind, understanding soul will eventually produce something like 'NNUE for Dummies'. There is a lot to keep track of here.

For this post I took some time for another search on a good introduction. After all, with so many people looking into NNUE, many of them must need basic knowledge. Youtube is often a good start for tutorial material, but the NNUE videos it suggested were about experts analyzing a game where one of the engines used NNUE.

More promising was Stockfish NNUE - The Complete Guide (yaneu.com). Excluding the resources in Japanese, it still offers many good leads. One obvious choice that I had managed to overlook was the 'Discord for Stockfish' page, specifically #general-nnue-dev. Who could explain NNUE better than the people who had been its early adopters?

Discord isn't for everyone. If you're not interested in a subject technically, it's probably over your head, which has been my general experience with it. Having only dabbled with it in the past, I was faced with a steep learning curve. First, here's a Q&A extracted from the NNUE FAQ. The last question was the most informative to me:-

Q: Is NNUE an opening book? • A: No. It is purely an algorithm for the evaluation function. Classical handcrafted evaluation functions are terrible in the opening.

Why the emphasis on openings? Perhaps because it's the phase of the game where evaluation functions are weakest. I've looked at engine evaluation several times in the past:-

Since I use engines for practical play, I'm well aware of their strengths (lots of these) and weaknesses (few of these, but they exist). Back to the NNUE FAQ:-

Q: What makes NNUE run much better with traditional AB/minimax engines on CPU? • A: The neural net used for evaluation is very sparse compared to UCT/MCTS engines on GPU, and the code is optimised for modern CPU instruction sets with vector intrinsics, both which allow for much faster calculations of the evaluation function necessary for AB/minimax search on the CPU.

Q: Is NNUE a library like Fathom for Syzygy tablebases? • A: No, each engine developer will have to manually port NNUE to their code base, or write the algorithm from scratch.

Q: Is NNUE related to Leela Chess Zero? • A: No. NNUE is descended from linear neural networks used by shogi engine developers since the early 2010s, while Leela Chess Zero is descended from the convolutional neural network based go engine Leela Zero, which itself is based upon Deepmind's AlphaGo Zero from 2017.

Q: Is it possible to train a NNUE net from zero like the T10 Leela nets? • A: Yes. Although the neural nets are typically trained with the help of the evaluation of the engine used for training, the lambda parameter in the training indicates how much the evaluation is used to help train a neural net, and setting lambda equal to zero means no evaluation is used to help train the net.

Q: Does this make NNUE zero? • A: No, because there is chess knowledge handcrafted into the various neural net architectures used in NNUE themselves.

Q: What is the most commonly used architecture used for NNUE? • A: Halfkp. 'k' stands for 'king', 'p' stands for 'piece', and 'half' refer's to the player's own king: put all together, 'halfkp' refers to the fact that the position of the player's own king and the relationship between the player's own king and every other piece on the board gets encoded into the first layer of the neural net.

Long story short : NNUE gets to the essence of handcrafted evaluation functions. Those FAQ explanations lead to as many questions as they answer, often a sign of being headed in the right direction. I'll come back to the subject after I've had some time to orient myself. I hope the time will be well spent.

20 September 2020

The Light at the Center of the Board

The last time we saw an artsy photo in the this blog's series of Flickr Favorites was Dora Maar, Weeping Woman (June 2020). Compare this to 406 Results for "chess" on Artsy.net.

Light © Flickr user CaptSpaulding under Creative Commons.

The description said simply,

There is always a little light somewhere.

One of the three groups to which the photo belongs is the All Free Pictures group pool (Creative Commons and Public Domain). Of the 242.977 photos in the group only 62 results appear for a search on 'chess'; few of them are familiar even though I've been following the theme for years. Compare this to 1909 results for 'cat' or 1016 results for 'dog'.

18 September 2020

Nine Chess Variants

Remember the post Non-random, Non-castling (December 2019)? It went something like this:-

Former World Champion Vladimir Kramnik has an idea: '[VK and DeepMind] tasked AlphaZero with exploring a variant that prevented either side from castling, trying different opening moves from both sides.'

If you don't remember that post, it's probably because you don't follow my chess960 blog, where it appeared. GM Kramnik resurfaced this month with a slew of similar ideas. You can explore them in New AlphaZero Paper Explores Chess Variants (chess.com):-

In a new paper from DeepMind, this time co-written by 14th world chess champion Vladimir Kramnik, the self-learning chess engine AlphaZero is used to explore the design of different variants of the game of chess, with different sets of rules.

While I was writing this current post, Chess.com updated their page to announce:-

On Friday, September 18 at noon Pacific time (21:00 Central Europe) Chess.com is hosting a round-table discussion streamed live on Chess.com/TV with GM Vladimir Kramnik, IM Danny Rensch and researchers of Deepmind discussing their latest paper in which AlphaZero explores chess variants.

Since that discussion will take place after my bedtime, I'll come back to it next week. It's been a while since I last ran a series on AI/NN, like these:-

  • 2018-07-27: Chess Piece Recognition • 'Let's return to the series last seen in The Limits of Image Recognition (June 2018).'
  • 2019-03-08: Closing an AI/NN Chapter • 'It's finally time to close the AI/NN series that I've been running for the last five months.'
  • 2019-09-13: Beyond AlphaZero • 'For the last two months, I've used this blog's Friday post to wander around topics relevant to AlphaZero.'

GM Kramnik's latest ideas might promise a wealth of new material related to AI/NN.

17 September 2020

2020 CJA Awards - Part 1

It's been more than a month and a half since I discussed the 2020 CJA Award Entries (July 2020), and at least a month since I would have liked to discuss the awards themselves. I split last year's post '2019 CJA Awards' into two parts -- Part 1 and Part 2 (both August 2019) -- first to discuss the process, then to discuss the awards. I have to do the same this year.

My '2020 Award Entries' post was fairly critical of the CJA award process:-

To sum them up in a word -- it looks like a 'botch'.

In past years, any criticism of the award process was taken as a personal affront by the award winners, as though I had criticized their own work. I was half expecting to get a similar response this year, so I was pleasantly surprised to receive a conciliatory email from Joshua Anderson, President of the CJA Awards. He wrote,

I thought I would reach out to you concerning your post and address some of the various points that you raised.

About my observation that there were two categories of nomination -- USchess and non-USchess -- he wrote,

The awards actually had three groupings, though due to some technical difficulties there was a bit of a delay in getting the entries from America Chess Magazine, listed. They are up now.

Indeed they are visible on the same page I linked in the previous post : CJA 2020 Awards [Entries] (chessjournalism.org). As for the other glitches I mentioned, Anderson explained,

The website will be moving in a few weeks as our new webmaster and the current platform do not mesh well, so our webmaster has arranged for us to move to a site that will allow us many more options. [...] Was it a down year? Yes, we were a little light in entries and there were definitely some communication breakdowns as our new webmaster and I had a couple of little miscommunications that routinely happen when you have new people coming into positions. [...] We will have the new website in a couple of weeks and this should allow us to make the awards much more available to the general public, so when you come back in 2021, you should be able to find things much as you did the previous couple years where you can access the entries, etc.

Having spent my adult life in Information Systems, those are explanations that I understand and accept, especially coming from a volunteer organization like the CJA. Although the award announcements are accessible on a couple of other sites, I'll allow a little more time for the move to Chessjournalism.org.

14 September 2020

TCEC S19 DivP Chugging Along; CCC15 Halted

In our fortnightly look at the two top engine vs. engine competitions, this post might turn out to be one of the shortest in the series. First let's summarize the situation from two weeks ago, as reported in TCEC S19 DivP Started; CCC15 in Brackets (August 2020):-

TCEC: Fire and ScorpioNN qualified from League 1 (L1) into the Premier Division (DivP), which will run for almost three weeks. The top two engines will qualify into the final match. • CCC: CCC15 uses a straightforward bracket structure starting with a preliminary round-robin equivalent to 12-game mini-matches. Stockfish won the preliminary event ('Round 1') by a significant margin. The 'Round 2' matches are underway.

Now let's skip ahead to today's post and review the current situation.

TCEC: DivP has reached the fifth of eight all-play-all rounds. Stockfish and LCZero have the same score, giving them a comfortable lead over the next group of engines. The schedule seems to have slipped since my previous report, but the event should finish before the next report in two weeks.

CCC: Because of technical problems, the CCC15 'Round 2' matches were halted about half way through. The explanation is:-

!next • CCC's GPU server is out of service. It went offline after reporting a host of issues: GPU fan issues, CPU VCC issues, bad DIMM, temperature issues with the CPU and GPU. [...] We don't know details of when it will be back in service.

The site is currently running a series of CPU-only exhibition events.

[For further information from the various stakeholders in the engine-to-engine events, see the tab 'TCEC/CCC Links' at the top of this page. • NB: Leela = LC0 = LCzero]

13 September 2020

A Fast Paced History of Chess

This video, from Youtube channel 'The History Guy' (subtitled 'History Deserves to Be Remembered'; currently 853K subscribers), starts,

Playing games is big business. According to 'Business Insider', the worldwide video gaming industry earned about $120 billion in revenue in 2018. The web site 'Statista' values the worldwide boardgaming industry at $7.5 billion. And it's not exactly a new thing -- the same web site values the industry around the game of chess, more than a millennium old, at around $190 million. A 2012 survey found that some 605 million people in the world still play chess on a regular basis.

Although that last statistic is often called into question, let's forget about it for a moment and watch the clip.

A Brief History of Chess (14:07) • '[Published on] Sep 4, 2020'

The video's description repeats that last statistic, then launches into the history.

A 2012 survey found that 605 million people play chess regularly, nearly 1500 years after the game was first played. The names of the pieces and the moves may have changed, but the rules that developed over a millennium and a half represent a culmination of many cultures and players that helped to develop the Game of Kings. The forgotten history of the game of chess deserves to be remembered.

Forgotten history? The video is a fast paced summary of chess's development that crams dozens (hundreds?) of facts into a little more than ten minutes.

In last month's featured video on this blog, Chess Movie 2020 (August 2020), I summarized some of the many comments. I could have done the same for the more than 800 comments against 'A Brief History', but time ran out. Maybe later...

07 September 2020


A couple of weeks ago, in the post CCC PGN II (August 2020), I tried to make sense of the large collection of engine vs. engine games held in the CCC PGN archives. Various efforts have been made to keep track of the files, each of which corresponds to an event conducted by the CCC. [It's been so long since I last expanded the acronym that I had to look it up. CCC stands for Chess.com's 'Computer Chess Championship'.]

The latest effort was a file in XLSX format. In the 'CCC PGN II' post, I took a look at it and noted,

The XLSX data is also useful for a number of other tasks. First, it can be used to crosscheck the older archives mentioned in the original 'CCC PGN' post. Second, I can use it to catalog the CCC-live weekly snapshots that I've been taking for the last year or so. [...] I didn't have time to complete either of those two other tasks. I'll try to do that another time

On the first point, I found:-

129 files in the older archive 'CCC Archive 3/6 - Pastebin.com' [2020-03-06], and
145 files in the newer archive 'XLSX data'

The difference of 16 files is explained by three duplicate file names in the newer archive plus 13 files not included in the older archive. As for the second point, the catalog of my own 'CCC-live weekly snapshots' is shown in the following chart. The asterisks ('*') indicate an event that I couldn't find in the XLSX data; this might be an error on my part.

The first line corresponds to the PGN file:-

CCC10 Bonus: CPU Classics

The last line corresponds to my post TCEC S17 L1 Finished; CCC13 Announced (March 2020). Why does CCC have so much trouble maintaining an index of PGN files for its ongoing series of events? Maybe they don't think it's important. If they would simply publish the list of new PGN files at the end of a CCC season -- currently CCC15 -- people who are interested in the files (like me) could take it from there.

06 September 2020

Square Off Chess Set

While I was developing my short list for this month's edition of Top eBay Chess Items by Price (March 2010), I noticed a large number of similar items. The following screen capture shows the top six of those items.

The item in the top left is titled 'Square Off Grand Kingdom Chess Set Limited Edition Black Smart Automated AI'. It sold for US $553.80, 'Buy It Now'. Its title is a straightforward concatenation of the phrases used in its description:-

Square Off • Grand Kingdom Chess Set • Limited Edition • Black • Smart Automated AI Chess Board • Board Measures 24" x 19"

At the present time (it hasn't always been this way), eBay includes the shipping cost in its calculation of 'Top Items by Price', and I noticed a large number of auctions -- not just the Square Off items -- with the shipping cost reaching three digits. The 'Square Off Black' added $136.65 shipping, and the next two items in the image were:-

  • 'Square Off Grand Kingdom Chess Set. A Smart Automated Chess Board. BRAND NEW'; $362.05 + $119.08 shipping
  • 'Square Off Kingdom Chess Set. A Smart automated AI Chess Board'; $349.00 + $120.28 shipping

What exactly is this 'Square Off' set? Its web site, World's Smartest Chessboard | Square Off, lists four attributes...

  • Automated; ('your opponent’s piece moves on its own')
  • Connected; ('globally connected game-play')
  • Intelligent; ('20 levels of difficulty to challenge this chess set’s built-in AI')
  • Handcrafted; ('intricately carved pieces')

...and three contact addresses: two in India plus one in the USA. The 'Grand Kingdom Set' lists for US $469, and the 'Kingdom Set' for US $399, both with 'Free Shipping'. A note mentions that the engine is Stockfish 10.

Why the big interest on eBay? A blog connected to the web site has more articles on running a company than on playing chess. I suppose that eBay is a marketing tool to gain more widespread exposure. After all, it got my attention.

01 September 2020

September 1970 & 1995 'On the Cover'

Last month's 'On the Cover' post, August 1970 & 1995, featuring the top American chess magazine from both 50 and 25 years ago, 'celebrated two tournaments that were open to the amateur player'. This month we see a mixture of elite and amateur events.

Left: 'Lubomir Kavalek. Winner at Caracas.'
Right: '1995 Macy's / Excalibur U.S. Chessathon'

Chess Life & Review (50 Years Ago)

Don't Walk -- Run by Lubosh Kavalek • What does it mean to be a "runner" in chess? There are many kinds of grandmaster in the world. Some think that good prizes can be won by winning a few games and, by playing to avoid risk, drawing the rest. This is the "middle class" of grandmaster. But what happens if they lose a few games? Then their idea doesn't work. One should try to win every game. It is a little risky because of the possibility of losing, but if you do well you can be first in many tournaments, like Bobby Fischer, Bent Larsen and Victor Korchnoi. When you try to win every game and gain many points, then you are a runner. My time for running was at Caracas -- I just arrived there and ran.

I was happy when the USCF offered me the opportunity to represent the United States at the international tournament in Caracas June 19 - July 12. I thought that I must replace my Czechoslovakian flag as the Czech Chess Federation has protested against me twice already (in San Juan 1969 and Wijk aan Zee 1970). Most chess players run from one tournament to the next. When you are in that situation and have no country to go home to, you feel all at sea. But when I came out of the sea to Caracas and saw the American flag on my chess table, I know I was firmly on the ground.

Wikipedia's page Lubomir Kavalek explains,

When Soviet tanks rolled into Prague in August 1968, Kavalek was playing in the Akiba Rubinstein Memorial in Poland, in which he finished second. Kavalek, who had always hated Communism, decided to defect to the West rather than return to Soviet-dominated Czechoslovakia.

Kavalek finished first in Caracas, a full point ahead of Oscar Panno and Leonid Stein. He identified Lubomir Kavalek vs Anatoly Karpov; Caracas 1970 (chessgames.com) as his best game from the event.

Chess Life (25 Years Ago)

Not only was June 10th at Grand Central Terminal a great day for the media, but the 4th annual CHESSathon, sponsored by title sponsors Macy's and Excalibur, also provided a field day for photographers. as witnessed by what we believe to be an award-winning photograph of five-year-old Noah Belcher.

A few years ago I posted about the initial event in The First USCF Chessathon (September 2014). The four page story on the 1995 Chessathon, filled with color photos like those on the CL cover, was perhaps overshadowed by a second story introduced as a 'NEWS FLASH':-

The PCA is thrilled to announce that the 1995 Intel World Chess Championship will be held at the Observation Deck of the World Trade Center! Garry Kasparov and Vishy Anand will slug it out each Monday, Tuesday, Thursday and Friday at 3 PM starting September 11th and continuing until one player reaches 10 1/2 points. General admission $9.00 (plus $6.00 Observation Deck ticket), King Room VIP seating $75 per session. Tickets are limited, so order today!

This was followed by a second part of the 'On the Cover' introduction:-

WORLD CHAMPIONSHIP • The story broke in Germany, and was quickly reported on the Internet. The PCA World Championship match between Garry Kasparov and Viswanathan Anand will be held at the World Trade Center Observation Deck in New York City, beginning September 11th.

From the other side of the world, FIDE Challenger Gata Kamsky received word from FIDE Secretary Casto Abundo that no bids had been received for the Karpov — Kamsky match, as of the deadline of July 1st. FIDE suggested that the federations of the two participants split the organization (and cost) of the match.

As the result of a joint FAX from Karpov and Kamsky, FIDE President Campomanes has extended the bidding deadline until 17:00 hours. (Switzerland Time), September 15, 1995, conditioned on the match being organized and finished in 1995.

The acronym PCA refers to the Professional Chess Association. For more about the organization, see my page World Chess Championship : FIDE/PCA Chronology.