Rating rules

Solvers’ rating

The rating is an integer numerical value which shows the solving strength of a solver. A solver gains it by solving at two approved / rated tournaments.

A rating can be gained at the WCSC, ECSC, WCCC Open, or other tournaments which fulfil definite criteria.

Ratings are calculated after each tournament. A rating list is published four times a year. It is calculated on the basis of the results of solving tournaments completed (including the report) by the end of March, June, September and December. If a tournament starts in one period and is finished in another period, the ratings of solvers are taken from the rating list valid at the start of the tournament, and the tournament is included in the period when it is finished. In case that at the same tournament different tables are produced (like one extra for juniors) ratings are calculated only for the major tournament.

The WFCC gives authority to a person(s) or a commission responsible for calculating ratings according to the approved formulas. An Excel macro has been developed for help.

Criteria for acceptability of tournaments
at which ratings and norms can be gained

At least 10 rated solvers (15 rated solvers from at least 3 countries for gaining norms) should compete in the tournament.

The selected problems should be originals or alternatively unknown published problems. The selected problems should show a clear theme and a good level of quality and difficulty and should represent different styles.

For tournaments organised according to WCSC rules, the full coefficient may be used to calculate ratings.

For other tournaments at most one half of the normal coefficient is used to calculate ratings. In those tournaments there should be at least 12 problems of different types to solve. Problems for solving can be chosen from seven groups: twomovers, threemovers, moremovers, endgames, helpmates, selfmates and fairy chess problems. At the tournament at least 5 groups with at least 2 problems must be represented. No group can be represented by more than 3 problems. The tournament could be divided into several rounds and/or days. If all problems are not given the 5 points each the tournament coefficient is corrected for calculating ratings. When fairy problems are included at the tournament it is recommended that the corresponding fairy conditions are announced at least two months beforehand. This is obligatory for the WCCC Open and it must be announced on the WFCC site and on the WCCC organiser’s website if it exists.

All tournament documentation (problems with solutions, complete list with the results and ratings, judge’s statement on the competition acceptability and possible complaints, etc) should be sent to the responsible WFCC representative (committee) within 30 days after the end of the competition. The representative (committee) has the right to confirm or not the acceptability of the tournament and determines the tournament coefficient. The final decision is approved by the WFCC.

Criteria for gaining norms

Norms for the titles International Solving Grandmaster of the FIDE (GM), International Solving Master of the FIDE (IM), FIDE Solving Master (FM) can be gained in a tournament if at least 5 solvers with current rating of 2550 / 2450 / 2350 respectively participate in it.

A solver obtains a GM / IM / FM norm when he/she achieves a performance rating of at least 2650 / 2550 / 2450. The solver must be placed within the number of solvers with the qualifying rating of 2550 / 2450 / 2350 (i.e. at least sixth place when there are 6 solvers with the qualifying rating of 2550 / 2450 / 2350).

Criteria for gaining titles

International Solving Grandmaster of the FIDE: A solver must gain a norm 3 times (at least once at the WCSC or ECSC) and achieve a rating of 2550.

International Solving Master of the FIDE: A solver must gain a norm twice and achieve a rating of 2450.

FIDE Solving Master: A solver must gain a norm twice and achieve a rating of 2350.

The obligatory rating may be achieved anytime (i.e. at any official rating list or as a current rating after a tournament).

(This version of the criteria was accepted at the PCCC Congress in Wageningen 2006. A small change in the criteria was accepted in Rhodes 2007. Further changes were accepted in Crete 2010 and Berne 2014.)

Rules for rating calculation

The basis for calculating ratings at a solving tournament is the average of ratings of all solvers with ratings (AveRat) and the average of achieved results of those solvers (AveRes).

AveRat = average rating of all solvers with ratings (subtracting by 1600)

AveRes = average result of all solvers with ratings

A rating for a solver without a rating:

It is calculated as a performance rating (PerfRat), i.e. a temporary rating achieved by a solver at a tournament upon the formula:

PerfRat = AveRat × Res / AveRes

Res = result of a solver achieved at a tournament

Solver’s first rating is called half-rating. At his next tournament he gets another half-rating. The average of all half-ratings is calculated and put to the rating list.

Change of a rating for a solver with rating:

The expected result (ExpRes) is calculated for all solvers with ratings upon the formula:

ExpRes = AveRes × Rat / AveRat

Rat = rating of a solver from the last rating list

The expected result might exceed 100% of the winner’s result. In such a case the corrections (CorrExpRes and CorrPerfRat) are made upon the formulas:

CorrExpRes = AveRes + (ExpRes – AveRes) × (MaxRes – AveRes) / (MaxExpRes – AveRes)

CorrExpRes = corrected expected result (cannot exceed 100% of the winner’s result)

MaxRes = result of the winner

MaxExpRes = the highest expected result before correction (higher than the winner’s result)

CorrPerfRat = AveRat + (PerfRat – AveRat) / (MaxPerfRat – AveRat) * (MaxRes * MaxRat / MaxCorrExpRes – AveRat)

CorrPerfRat = corrected performance rating

MaxRat = the highest solver’s rating

MaxPerfRat = performance rating of the winner

MaxCorrExpRes = the highest corrected expected result

Change of rating (ChOfRat) is calculated from the difference between the expected result and the achieved result upon the formula:

ChOfRat = KT × (Res – ExpRes)

or in a case of correction:

ChOfRat = KT × (Res – CorrExpRes)

KT = tournament coefficient (from 1 to 4)

If the problems at the tournament are not given 5 points each the KT is corrected upon the formula:

CorrKT = KT × 5 × N / AbsMaxRes

CorrKT = corrected tournament coefficient

N = number of problems at the tournament

AbsMaxRes = theoretical MaxRes at the tournament

New rating is calculated upon the formula:

NewRat = Rat + ChOfRat

All calculations are made to the second decimal place. Ratings are published as integers. For publishing use the ratings are increased by 1600.

After five years of non-participation in rated tournaments, a solver will be expelled from the rating (half-rating) list. Should he participate in the future, his original rating (but not half-rating) will be accepted.

Ratings are calculated after each tournament. An updated rating list is published four times a year (at 1st January, 1st April, 1st July and 1st October).

ANNEX

Tournament coefficient

A frame for coefficients for tournaments organised according to the WCSC rules:

Coefficient
Criteria for tournament
4
WCSC, ECSC
3
WCSC-type tournament for norms
2.5
participation of at least 5 solvers with a rating of 2300 or higher
2
participation of at least 5 solvers with a rating of 2200 or higher
1.5
participation of at least 5 solvers with a rating of 2100 or higher
1
Other tournaments organised according to the WCSC/ECSC rules

A frame for coefficients for tournaments organised according to other rules:

Coefficient
Criteria for tournament
2
WCCC-Open
1.5
ISC, not-WCSC-type tournament for norms
1
Other tournaments

The representative (committee) has the right to confirm or not the acceptability of the tournament and determines the tournament coefficient.

This version of the rules was accepted at the PCCC Congress in Wageningen 2006. A change in the publication of the rating list was accepted in Rhodes 2007.

A change regarding negative NewRat was accepted in Rio 2009.

Changes in the criteria of gaining norms and titles were accepted in Berne 2014.

 

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