Russell Sherwood


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Even simpler guide to the new ICCF Ratings system

Russell Sherwood  Saturday, November 4, 2023

ICCF New Rating System

Recently, ICCF moved to a new rating system. Several documents have been issued explaining the new system, but these tend to be difficult to understand for those without a Statistical background.


Below is a brief attempt to give a simple explanation of how it works: If you want to know more, it's back to the more detailed specifications!

The new system was designed with several objectives in mind – some explicit and some indirect benefits – including:

  1. Recognizing the increasing levels of draws within correspondence chess, especially at higher rating levels.
  2. Recognizing that the Elo formula utility is flawed within correspondence chess – What I mean by this is that with a typical Elo formula, the WLD statistics in a game between a 1900 and 2000 rated player are the same as those between 2400 and 2500 rated players!
  3. Recognize that not all results should be measured in the same way.
  4. That new players are an unknown quality – an 1800-rated player in an event could be very different things in terms of playing strength. This leads to the idea that games should be treated differently, dependent on these kinds of considerations.
  5. That a process of “leeching” rating points had been observed – players simply aimed to draw out games quickly to gain rating points.
  6. Several ways to game the rating system have been developed by players


So how does the new rating system now work…..


A player’s strength is now measured using two numbers, Rating and Rating Deviation.

Rating Deviation – What is it?

Rating Deviation is a concept that many players struggle with – it is listed as a measure of the uncertainty of a player’s rating – I prefer to consider it as a measure of a player’s activity.

In simple terms – the more games you play – the more games you finish – the lower your Rating Deviation will be.

When we think about this, the more games we complete, the more accurate the rating will be as a measure of our actual playing strength. Going a little deeper, the more games we have completed recently is also a better indicator of our playing strength – so the games we played 10 years ago have very little relevance on our rating today. 

A new player will start out with a very high RD (250), as they have completed zero games, but this will drop as they complete games and their rating becomes more stable.

Rating Deviation – How does it affect rating calculations?

If we examine the “Beginners Guide” we see that the level of RD has an impact on the benefits a player gains from a result.

The lower your RD, the less benefit (or loss) you will gain from a result as your RD increases.

The converse of this is also true.

The higher your RD, the more benefit (or loss) you will gain from a result as your opponent’s RD decreases.

 What does this mean – if you play a new starter or an inactive player returning, those results will have less impact on your rating but more on their rating than those against players with established ratings.

Rating Calculation

Now we know the impact the Rating deviation has on the rating formula, let us look at the formula itself.

  1. The new formula calculates different percentages for Win/Loss/Draw
  2. The benefits for these results are different depending on the ratings of the players – In simple terms, the higher the ratings involved the higher the benefit of a positive result.

The percentages for these results were based on several, recent, year's results.


What does this mean? Below are the charts used in the “Beginners Guide”.

The first shows the likely outcome based on the player and opponents’ results for a 1500-rated player, and the second shows that for a 2500-rated player.

A comparison of graphs with different colored lines

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A comparison of graphs with red and blue lines

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Without going into any mathematics, we can see that the results curves for Win/Loss/Draw, whilst similar in shape, are pegged at different levels. The main takeaway from this is that draws become more common the higher the rating involved, and the consequence of this is that those draws have less impact on a player's rating. Decisive games become less common as ratings increase, so the benefit of these results also increases.

The Impact of the Rating Deviation is to modify these benefits as outlined in the RD section.

ICCF have two useful resources – the first is the details of the rating formula – If you really want to delve into the mathematics of the system, read this. If you do this, I suggest putting your own results in to work through. The second is the Calculator, which allows you to plug in numbers – do beware, this is for illustration only, rather than definitive.

As a final note - it is now incorrect to refer to an ICCF rating as an ELO rating (Capitalized or not) as we have moved away from the ELO system - it is now simply ICCF rating.


Predict a Move

Russell Sherwood  Saturday, June 17, 2023

In high end Correspondence chess draws are the most likely result. This can have a demoralizing effect on Correspondence chess players and make progression in multi-round events difficult to achieve or control.

Many solutions to this have been suggested, but almost all of them fail to gain support from players for three reasons:

  1. They change the fundamental nature of the game itself – so it is no longer chess but a sub-variant of the game.
  2. They tend to introduce randomized features, which reduce the relative skill component of the game.
  3. The rating system can become distorted through those randomized features.

The Predictor Tie break addresses all these concerns.

The game of chess is the same. The game is played in the same manner as currently, but with an important addition -Each game becomes a mini-match between two players, with the one who predicts the most moves of their opponent winning that mini-match. (2 for a win, 1 for a draw, 0 for a loss). These mini matches are then totalled for the event and used as a tie-break, after all, others (Wins, SB and so on) to determine placings. The prediction count is only used for 

Looking at the issues above, (1) It's still chess (2) No Randomized features have been introduced (3) The rating system is not affected.

If adopted on a wider scale this could be programmed onto the ICCF server (similarly to conditional moves) and for test events an Umpire would be utilized, who the players would send a sealed file prior to making each move.

Other positive outcomes to this approach:

  1. Players who simply play Stockfishes 1st choice move will not do very well on this tiebreak.
  2. Players who rely too much on previously completed games or analysis will also struggle.
  3. To do well, players will need to go down new avenues of play, which can be risky but also a lot more fun!

It is worth mentioning that some players will believe that if they do not play the 1st choice of the engine, they will be on a path to defeat. This is true if they go down lines where there is only one “Good” move, however, if skill is applied, they will navigate to those positions where multiple playable moves exist (ideally for their own side!).  This will be a fine line but means that skill will have a more say in the outcome of a tournament rather than just simple brute computing power.

An ICCF proposal from Slovenia seeks to add this officially to ICCF rules, as an option. Proposal (  This is near identical to the outline above, with a few technical minor technical details.

The WCCF will be seeking to organise its own trial event in near future. It will be free and unrated to encourage both participation and risk taking.


Pulled up by your Bootstraps

Russell Sherwood  Thursday, April 20, 2023

I've been playing with predictive models recently and whilst not developed for the CDCCC specifically, I have applied it to the event.

A very basic overview of the model is that it predicts the results of the pairing of the event, using a highly modified Elo model, taking into account both draw rate and White vs Black result expectation. This model is then run many times over (many thousands of time)

After two results.....

What does this mean - in many thousands of simulations, Lancashire came 1st 16.9% of the time, 2nd 13.99% and so on.

From a positive point of view, this does suggest that the draw did not give any team a significant advantage...with the differences being down to the overall difference in rating!


So all to play for. This will become much more interesting as results start to roll in.



14th ICCF Veterans World Cup (VWC14)

Russell Sherwood  Thursday, April 13, 2023

14th ICCF Veterans World Cup (VWC14)

Friday, 31 March 2023: Tournament Announcement

The ICCF Congress decided that following the great popularity of this tournament amongst older players, new Veterans World Cups would be started every other year. Working in collaboration with ICCF, the Netherlands Federation for Correspondence Chess (NBC) will organize the 14th Veterans’ World Cup tournament.

The first stage of the 14th ICCF Veterans World Cup will start on 1st September 2023.

As with the previous VWCs, the tournament will be organized in three stages which will allow several players from each group stage to advance to the semi-finals and final. The number of promotions will depend on the total entries received. It is envisaged that groups at the preliminary stage will comprise 11 players (10 games) or 13 players (12 games) played by webserver with a rate of play 550 days Triple Block without "guaranteed time" (PR and SF). And only in the final with "guaranteed time". 


The 14th ICCF Veterans World Cup is open to all players who are 60 years old or more at the start date of the tournament. Therefore, players have to be at least 60 years old on 1st September 2023. 

Prize fund

A prize fund of €6,000 will be available for this tournament as agreed at the 2013 ICCF Congress. The exact distribution of this prize fund will be determined once the number of entries and groups is known. Medals will also be awarded to those finishing in first, second, and third place in the final. 


Players may enter:

  • through their federation (contact your federation for the amount of the entry fee)
  • where eligible, via the ICCF Direct Entry system. The entry fee by Direct Entry will be € 9.00 for each preliminary group entered.

Although the number of preliminary groups which each player may enter is unlimited, no player will qualify for more than two semi-final groups or for more than one place in the final.

Entries should be made via the server from the "New Events" page. It would be appreciated if delegates would approve entries made through their federation via the server as soon as possible after receipt rather than delay them until the closing date. Entries sent by email directly to the tournament organizer by delegates or players will not be accepted.

The closing date for entries is 25th July 2023.

All veteran chess players are heartily invited to enter this tournament, both for the enjoyment of games and for friendly contact/communication with senior players around the world.

Federations are kindly asked to give tournament-wide publicity to their veteran players.

Jörg Kracht
ICCF Non-Title Tournament Commissioner

Frank Geider
ICCF World Tournament Director

Joop Jansen
NBC Delegate and Tournament Organiser

ICCF Mid Term Elections

Russell Sherwood  Saturday, April 8, 2023

According to ICCF Statute 22(1) and the ICCF Voting Regulations and Electoral Procedures, paragraph 5, the following procedures and timescale will apply for mid-term appointments to the ICCF Executive Board.


1. Nominations are invited from respective Member Federations for the following position:


Finance Director


It is the right of each member federation to nominate candidates for the above position, providing that:


1.       The nominee is a current member of their Federation (which must be a full ICCF Member Federation), and,

2.       The nominee has confirmed their willingness to be nominated.


Nominations from Member Federations should be sent to the General Secretary, Michael Millstone ([email protected]), with a copy to the Auditor, Paul Scott ([email protected]), to reach them no later than April 30, 2023.


Each nomination should include a written declaration from the candidate indicating their willingness to be nominated and a personal statement (optional) providing information supporting their candidacy.


When all nominations have been received, the information will be issued to all member federations immediately; after that, the nomination windows close to enable them to consider all the candidates and decide upon voting preferences.  




The election will begin on May 14. 2023 and continue until May 31, 2023, 23:59 GMT.


The candidate with the most votes will be elected. In case of a tie for most votes, the President will decide.


The winner’s announcement will occur immediately after the election, and because the position is vacant, the winner will assume the position immediately.


If no nomination is received from the Member Federations for any Executive Board position, the Executive Board will be empowered to appoint an Official.


Personal statements of candidates should not be published in commercial magazines/internet sites, etc., until after they have all been circulated by ICCF to the official delegates of member federations (as below).


Election campaigning/soliciting for votes, etc., should only occur after the complete list of candidates, accompanied by their personal statements, has been officially released by ICCF, as indicated above.



Michael Millstone

ICCF General Secretary

[email protected]


How not to draw every game - Part 1 Introduction

Russell Sherwood  Friday, February 24, 2023



It’s an undeniable fact that the proportion of games ending in a draw is growing at all levels of the game. Whilst some believe this is almost wholly due to the increasing strength of chess engines, this I believe in incorrect and some of this increase is self-inflicted by the correspondence chess community.

How is this self-inflicted? By a very large number of players using a near identical approach, using near identical tools and equipment. This approach, which I will outline in a moment, was good enough in many cases to enable the player to reach a 2300+ Elo rating, but when continued to be used at this level, against players using the same approach leads to our current situation.

So, what is this generic approach:

  • Use the latest Stockfish.
  • Use the highest specification hardware the player can afford (or cloud engines)
  • Let the Engine run for a long time (or red in Chessbase terms)
  • Use an opening book based on recent high-rated ICCF games and play the statistical best option moves.
  • Play the first move choice of the engine.

The issue is that the draw becomes almost a self-fulfilling prophecy, with the same drawish lines being played over and over.

Is there another way? Yes! Does it guarantee victory? Hell no, but it does increase the changes of victory by a number of percentage points and allow for a far more interesting, less sterile game to be played.

There is no single alternative approach, if that was the case, we would be exchanging one generic approach for another.  So what do we need to do to improve our chances? To explore a number of potential areas, it is best to consider an anti-goal. What is that, you may ask? I came across the concept a few years ago during a (work based) annual review. Most are familiar with the concept of goal and objective setting, probably using the SMART methodology. Anti-Goals are designed to help to understand how to achieve a goal – so in this situation our anti-goal would be how to devise a plan to draw every game – these become the very behaviours and methods we avoid achieving our actual goal.

Before we move onto the first section, it is worth noting the predictability of human behaviour in those who also said “Losing is another option” or some variation!

So if we were looking to draw every game we would probably look to:

  • Use Same Engine as Everyone else!
  • Use Same Openings as Everyone else!
  • Use Same Databases as Everyone else!
  • Simply IA max time approach
  • Take and offer draws early.
  • Seek draws in Opening Strategy
  • Don’t prepare for the Opponent.
  • Don’t Take risks.
  • Play quickly.
  • Believe that all zero evaluations are drawn.
  • Believe that all zero evaluations are the same.
  • Be still playing a book line by move 20.
  • Not understand how to use the tools they have effectively.
  • Don’t look for the point where you drew!
  • Don’t look for new methods, ways to get an edge!
  • Not have a winning mindset
  • Believe that the openings played by the highest rated players are the best.
  • Use the same opening books as others.
  • Believe that greater depth always gives a better evaluation.
  • Believe the same approach will give different results.
  • Be afraid to experiment.
  • And many more

Come back next week for the first section – Mindset. To be published on the 3rd of March.

Correspondence ChessICCFWCCF

10 Tips to reduce your CC Energy Use

Russell Sherwood  Sunday, September 18, 2022

This article is inspired by an interesting discussion took place about Energy use in WCCF Facebook Group, This came out of the Energy price hikes taking and predicted to take place in the UK.  Most of these are obvious, but some are not quite so!


  • Turn off your monitor and External speakers. If you are utilizing your machine for long analysis – turn it off!


  • Set your PC to sleep after a specific time if you run overnight – If you are lucky enough to have Economy 7 and set a PC to review positions overnight – if you know it will finish at a specific time then set your PC to shut down after that point. The same goes if you use a laptop, ensure it is charged overnight and run down in the day.



  • Utilize Automation – A significant change I made a few years ago was to write Automation processes. Chessbase does have a basic functionality, and even this will allow more analysis time to be squeezed into the same time.


  • Check if the Engine has a green mode – a Few do, this lowers energy consumption by a few percent.


  • Clean out the Fans on the PC – Simple one this – make sure the fans inside your PC and the vents are clear of dust.



  • Make sure there is space around the PC – Make sure your PC has room for the Air to circulate, this will keep the PC cooler and reduce the need for Fans to work.


  • Consider Natural Cooling – Little bit odd this – a few years ago I had an old PC in the attic as part of my cluster. During the winter, this room was rather cooler… is worth saying that the room whilst cold was dry.



  • Reutilize analysis (Learning books/ AQ) – If you are structured in your analysis, then often you can avoid using energy by already having considered the analysis of certain positions.


  • Consider the relative costs of local vs online analysis – there are a number of online clusters available – with the price of energy different in different parts of the world it is worth considering if online cluster support can be purchased cheaper.


  • Are you using the right Equipment for the Job? Is a Laptop or high-end PC right for the task in hand?

and thats a wrap! If you dont want to reduce your CC then these tips should help make a change in the right direction!


Silli Tie-Breaks

Russell Sherwood  Sunday, September 18, 2022

An explanation of the Tie-breaks in the Silli system.

There is a more detailed explanation on but this is more related to the internal working of the pairing formula.

In simple terms in the Silli system you get a set of opponents from determined by a formula. An analogy I find useful here is to imagine a massive round clock – in this case with the numbers 1-25. Each number of the clock will have a predefined set of opponents. This set of opponents is defined by a formula. Which number on the clock you get determines the set of opponents and the formula tends to balance the quality of opposition.

The Tie breaks are different on a Silli Event

  1. Score – the sum of your results
  2. Buchholz cut 2 - – This is the sum of the scores of your opponents, disregarding the lowest two.
  3. Buchholz cut 1- This is the sum of the scores of your opponents, disregarding the lowest one.
  4. Buchholz – This is the sum of the scores of your opponents
  5. Buchholz 2nd stage – This is the sum of each of your opponent’s Buchholz score multiplied by your result
  6. Wins – The number of Wins you have


Lets consider this for a moment…..

The better your results (Win, Lose, Draw) the higher up the table you will be . If these are tied then the number of wins, the quality of opposition, their results, and your results against them will be taken into account.

So as an example: Cross Table (



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If we look at the 2nd place Email Klaus




Graphical user interface, application

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The BC Score is the sum of opponents. For the BC1 we remove the lowest score (zero in the case, so it’s the same result) for the BC2 we removed the next lowest scoring opponent (a score) of one, reducing our the BC2 to 58.

The BC-2nd Stage is the sum of the opponents BC scores.

I hope this helps!

Good luck in the event.

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