# Handicap Games

Does OGS give out handicaps for 19x19 the same way it gives them out for 9x9? For example, let’s say a 9k versed a 5k. The 9k would get four handicap stones on 19x19, but what about 9x9? I would see this as a huge advantage for white.

after i saw your question, i clicked on 9x9 games and see if there were any handi stones

and the result is that no matter how strong the other player is, no handicap stones were given

this is just based on what i saw
most likely is handicap stones can be given but more often than not handicap stones aren’t necessary

you can imagine you’re 1k giving 9 stones to 10k on 9x9, how do you win? lol

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Handicap in 9x9 does exist, although many games are played without it(such as my game against a 6d).

I think I have given two stones to a 25k when I was a 20k, but I don’t remember much about this. They also sometimes give reduced komi instead.

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In my childrens club I calculate handicap on 9x9 by dividing the rank gap by 6.

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The system I’m familiar with says half the stones for 13x13 and a quarter for 9x9

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I suppose you mean a quarter for 9x9, so 1 stone per 4 ranks.

I think that scheme is quite tough for white.

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I saw a japanese pro talking about handicap for a smaller board size, specifically 13 x 13:
“13路では置き碁より逆コミの方が面白いゲームになると思っていまして” (translation: I believe, in 13 board, reverse komi makes for a more interesting game than on-board handicap.)

His article does not mention a method for calcing such reverse komi for 13 x 13 though.

For 19 x 19, the following article links to 2 ways to calcing reverse komi, one is a table made from game data, the other a formula using ogs rating.
https://senseis.xmp.net/?ReverseKomi

In theory, someone versed with data mining could make a similar thing for smaller boards as well.

EDIT:
the following is a discussion about handicap vs reverse komi. there is an interesting comment wrt their effect on a game.

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I asked KataGo to estimate the komi value of handicaps on different board sizes.

This is what it says (Japanese rules and standard placement of handicap stones):

9x9
h1 = 5.5 komi
h2 = 15 komi
h3 = 24 komi
h4 = 45 komi
h5 = 71 komi

so roughly 15 points per full handicap stone

13x13
h1 = 6.5 komi
h2 = 18.5 komi
h3 = 30 komi
h4 = 44 komi
h5 = 51 komi
h6 = 63 komi

so roughly 11 points per full handicap stone

19x19
h1 = 6.5 komi
h2 = 19 komi
h3 = 31 komi
h4 = 46 komi
h5 = 59 komi
h6 = 74 komi
h7 = 87 komi
h8 = 102 komi
h9 = 112 komi

so roughly 13 points per full handicap stone

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Yes, I did ^^. I should stop posting when I’m sleep addled.

You should be aware that KataGo has no training experience with handicaps greater than 5 on a 19x19 board, or greater than 2 on a 13x13 board, and none at all on a 9x9 board.

So it’s figuring out everything entirely by pure guessing and extrapolation, and based on its initial shallow reading from the position you gave it with so many stones that it has never seen before - so it’s not necessarily accurate for larger handicap sizes.

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