Steps between Ranks
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The steps between amateur ranks correspond to the handicap difference. When a 6 kyu plays another 6 kyu, either player can take Black. Over several games, they would alternate. There should normally be no handicap and White would get komi to offset Black's advantage in moving first. When a 6 kyu plays a 5 kyu, the 6 kyu always is Black, and there is no komi (or only a half point to prevent jigo). So we say there is a one stone difference in the strength of a 6 kyu player and a 5 kyu player. When a 6 kyu plays a 4 kyu, it is a two stone difference in strength, so the 6 kyu not only takes Black, but puts two stones on the board before White makes a move. (0 or 0.5 point komi.)
6 kyu vs. 3 kyu, three handicap stones; up to 6 kyu vs. 1 kyu = five handicap stones; 6 kyu vs. 1 dan = six handicap stones; and so forth. In theory, a 20 kyu player should take a 19-stone handicap from a 1 kyu, and a 20-stone from a 1 dan. (In practice, handicaps larger than 9 stones are pretty rare. When the difference in strength between the players is greater than 9 stones, we just chalk it up as a Teaching Game, and accept that White will spend a lot of time proposing better moves for the weaker player, just so White can stay awake.)
The Korean gup ranks work essentially the same way (a 7 gup player would need three stones handicap to have a reasonable game with a 4 gup player).
Bill Spight: The traditional handicap scheme gives an advantage to White. In an even game, Black plays first and gives komi. If Black is one stone weaker, then he or she should take two stones and give komi. Or, reversing colors, White plays second and takes komi. If White is one stone weaker, then she or he should play first (i. e., play Black) and take komi. Either way, taking Black without receiving komi is an inadequate handicap for a one stone difference in strength. Similarly, taking 2 stones without receiving komi is inadequate for a 2-stone difference. And so on.
Jasonred: I think I finally got it. Going first, is worth half a stone, and every rank is worth one stone. And, komi is half a stone, because if A goes first, the advantage is x, B going first advantage is x, and the difference between the "who goes first" is one stone, i.e. the stone which was placed. So, we should always have komi, cause it's the only way to make up that half stone advantage.
exswoo: Proper Handicap = (Rank Difference) handicaps stones + 1 additional stone + komi for White.
Jasonred: I dunno... I think that Black should be given an "easier" handicap, by giving (rank diff) stones + reverse komi. It might seem like about the same, but in my humble opinion, now Black not only has a territorial advantage, but also can play defensively. "Forcing" Black to make up the komi by playing aggressively seems bad to me. I dunno for sure though.
Charles: In my view, one should never lose sight of the purpose of handicaps, which is to make teaching games more interesting and instructive. I don't think Go handicaps really lend themselves to tournament systems of any kind (they were used in the Oteai, but eventually phased out). Just about all known handicap systems do favour White; those with suspicious minds will ask Cui bono? about a given system, and will come up with the answer 'stronger players'. That being said, a handicap system that is a little light provides a reasonable environment for the rapidly-improving player. The spacing between ranks is a more serious issue than this one of first-play advantage.
If we were to put it into a chart...
Traditional New(?)
1-rank = 1/2 stone 1 stone 2-ranks = 1 1/2 stones 2 stones 3-ranks = 2 1/2 stones 3 stones 4-ranks = 3 1/2 stones 4 stones 5-ranks = 4 1/2 stones 5 stones 6-ranks = 5 1/2 stones 6 stones 7-ranks = 6 1/2 stones 7 stones 8-ranks = 7 1/2 stones 8 stones 9-ranks = 8 1/2 stones 9 stones
(You know, I looked at the chart under this after I wrote all this out and it looks like it does the same thing :) )
TakeNGive: Bill, is there a table somewhere that spells out handicap and komi combinations that give players of different strengths an even chance? The traditional scheme is the only one I'm familiar with.
Andre Engels: The 'class' system that used to be used in Europe, and can still be found in the Netherlands on club level, would be of that kind. In it, each grade is represented by two classes, the lower the class, the higher the grade. Class 20 and 21 represent 1k, the rest can be calculated from there. Handicaps under this system are equal to (d+1)/2, where d is the difference in grades. If this gets to a half number, say 4.5 stones handicap, komi (usually 5 points) is used to get to a full handicap - in this case either Black would get 4 stones plus 5 komi, or Black would get 5 stones with White getting 5 komi, depending on the local habits and the preferences of the players.
Skelley: This is the table we use at the Amsterdam Go Club, it works fine.
Strength difference Black White dan/kyu class[1] EGF rating stones komi 0 0 0-49 1 w + 6,5 1 50-99 1 w + 0,5 1 2 100-149 2 w + 6,5 3 150-199 2 w + 0,5 2 4 200-249 3 w + 6,5 5 250-299 3 w + 0,5 3 6 300-349 4 w + 6,5 7 350-399 4 w + 0,5 4 8 400-449 5 w + 6,5 9 450-499 5 w + 0,5 5 10 500-549 6 w + 6,5 11 550-599 6 w + 0,5 6 12 600-649 7 w + 6,5 13 650-699 7 w + 0,5 7 14 700-749 8 w + 6,5 15 750-799 8 w + 0,5 8 16 800-849 9 w + 6,5 17 850-899 9 w + 0,5
[1] The strength difference system that used to be used in Europe, and can still be found in the Netherlands on club level.
Sektor? I assume this entire discussion only explains the situation for a 19x19 game, so what about a 13x13, or even a 9x9 game? How is the number of necessary handicap stones calculated from ranks here? Or is there no 'official formula' for these situations?
Malweth I'd imagine there's no "official" formula because there are no official games. I'm sure there's a best use formula out there, though I'm not sure what it might be... I do know that as a 12k playing my 7d teacher I was able to win with 4 stones on 9x9 - so I think that the smaller the board, the more subjective handicap stones become (especially as it becomes more and more about tactics).
jfc: I recommend throwing these formula out the window and sticking to the Kadoban system. If you have no idea of the correct handicap then guess, play some quick games and change the handicap with each game. Once you think you know the correct handicap then switch back to the traditional 3 wins in a row changes the handicap.
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