McMahon explained by Christoph Gerlach
This translation was made in 2008. See also a 2021 Google Translate translation.
A key point is to ensure that all players in the rankings in, which is out of their nominal strength. They get each player at the start of the tournament a "MacMahonScore" (short MMS), which, with its skill level corresponds, for example,
Game strength MMS
20 Kyu 0 19 Kyu 1 18 Kyu 2 ... And so on
In a MacMahon tournament will be all the players (in simple terms) in the next round so coupled that A) Partie no repeats, so everyone gets an opponent, which he previously in the tournament has not had B) an opponent with a possible same MMS receives
After a round alter the results obtained the MMS a player -- He wins, the MMS to a point raised -- He loses, it remains the same MMS -- Draw (jigo), the MMS to a half-point increase
After each round, there are ordered by the MMS a new ranking. It is obvious that, for example, 5 rounds at a player in the rankings a 5 game strengths better other players may be obtained at best (win everything himself, the other must lose everything).
-- If a player suspends, MMS will be a half-point increase
Such players are still difficult to overtake in the rankings.
At the end of the tournament, so you have a new ranking, which essentially the rankings after playing strength is corrected for individual particularly successful or particularly bad results. This image many players use then for a correction in the strength of their own game: it is itself than 3 Kyu started at the end of the whole blithely between 2 Kyus, it is a great place themselves at 2 Kyu time, as in the place, there was finally in field claim. Runterstufen is not quite as usual, but one could make the same pattern.
MacMahon The system is particularly suited to that players with relatively similar skill level compare and reorder. The result list is just as improved sorting considering the results.
The main criterion for the ranking is the MMS. There are many players with the same picture there at the end of a tournament (as that much with the same skill level considered grossly), it is customary to the rankings between players with a MMS to refine ... And precisely because SOS and SOSOS come into play.
SOS = "Sum of Opponents Scores," German for "enemies points," calculated as a sum of MMS, as a player opponents had (possibly adjusted by using guidelines and suspended rounds, there are also rules was because only).
SOS assessed the average strength of the opponents they had. If two players with the same picture of a more SOS, which means nothing other than that he is probably in the tournament, on average, the heavier opponents and had thus achieving precisely this MMS greater performance than for the player, which has the lower SOS. So players with more SOS listed above, since they are most likely (mean then guaranteed) more than those with lower SOS.
SOSOS = "Sum of Opponents SOS" to German "sum of opponents points by the opponents" is a further refinement of SOS ranking.
SOSOS rated the average strength of the opponents of opponents.
How can it be that we had an enemy who had a high MMS (which is a lot even brings SOS), but only against himself "Luschen" has played, so players who ultimately own a relatively low MMS. Since then will be in the decimal place for these players but not 100% of the SOS in the bill received. This is superimposed on the more refined scoring SOSOS achieved.
But you could say that the main field is the only MMS is a major sorting. Only at the top of the tournament when it comes to the absolutely strongest player among those present to identify and SOSOS SOS should be used if possible.
Pl name Str Cl. MMS 1 2 3 4 5 Pt SOS SOSOS 1 Bao Yun 7d At 43 8+ 3+ 5+ 2+ 4+ 5 205 1023½ 2 Bin Cho Soek 7d Ham 42 5+ 6+ 4+ 1- 3+ 4 207 1021½ 3 Yang Zhiwei 5d F 41 9+ 1- 6+ 14+ 2- 3 205 1014 4 Yue Wang 4d Gel 41 10+ 12+ 2- 8+ 1- 3 205 1012 5 Zhou Li 5d F 41 2- 11+ 1- 23+ 8+ 3 203½ 1005½
... Pl = place, while the number of the player on the list. If the number is free, share space on the players, but the players are consecutively numbered line by line. = The name of the player, possibly reduced Str = strength, d = Dan, k = Kyu Cl. = The first three characters of the Go Club, where the tournament was specified MMS = MacMahonScore 1 to 5 = Game 1 to 5 rounds of the tournament. Displayed number is the serial number of your opponent in the round of the "Pl" column. Behind the numbers is the result, the most common are "+" = won, "-" and lost = "=" = undecided Pt = number of points in the tournament. Each victory is 1 point, a draw is a half point. SOS / SOSOS, see note above.
Concrete example interpretation: Cho Soek-Am from Hamburg, also in the first round against Zhou Li played and won. At the end, he had won four times and was ranked 2 of the tournament.