Deutsche Wertungszahl
The German rating of (short- DWC ) is a rating of chess, to compare the skill level of individual players.
Generally
The introduction of DWZ was decided by the German Chess Federation (DSB ) after reunification. Until 1 January 1993, the DWC was introduced across and replaced the Ingo system of the German Chess Federation of the Federal Republic of Germany and the NWZ- system of the German Chess Federation of the GDR. The DWC is similar to the Elo FIDE, but was further developed steadily over the years. During development, the experiences from the Ingo system and the NWZ- system were considered. The scale of the players thickness ranges from about 500 ( beginner) to about 2800 ( World Champion), in theory it is, however, open at the top and bottom. The evaluation of the tournaments will be made by DWZ speakers who pass on the acquired tournaments on the rating headquarters of the DSB, where the central rating (ZDB ) is performed. There, the deadline of a tournament is performed according to a chronological recalculation.
In contrast to the Ingo system a higher ELO means a higher skill level. The DWC is composed of an initial rating of as a measure of skill level and the index thereof by a - is disconnected " ". For players but do not have an ELO FIDE ELO FIDE ELO is used, provided with index 6 and adopted as DWZ. Players who have a FIDE - ELO have neither a DWC but have a national rating of ( NWZ ), it will be used and may be converted only into a DWC. The index is set equal to zero in this case.
Calculation of DWZ
Is the basis for calculating a Gaussian bell curve. For the calculation, an integral is used to determine the expectancy. Will be considered achieved results against opponents with a DWZ only at the chessboard.
Basic formula
The ELO is calculated as follows:
Expected and points scored
The points W obtained are the sum of the match results, with a profit than 1 point counts, one draw and one defeat than 0.5 points as 0 points. The expected points We calculated using the following approximate formula:
The expected points are calculated for each section and then added together. The exact values of the expected points can be seen in the table the German Chess Federation. The formula calculates a good approximation.
The development coefficient
Another component is the development coefficient E. It consists of the basic value E0, the acceleration factor a and the brake B surcharge:
With
E also depends on the number of previously evaluated tournaments. The index i of the first ELO is 1 and is incremented after each tournament evaluation by 1.
So again, the following applies:
In the last step E is rounded to the nearest integer.
Calculating a first- DWZ
To calculate a "First DWC ", the basic formula not be used. On the basis of a percentage point yield a DWZ difference is determined by the probability table. To this value, adding the DWZ average of the opponents and receives a "First DWC ".