MacMahon Tournament with handicaps not working

My club has set up a MCMahon tournament with handicaps allowed. However some players are reporting that despite there being a big difference in strengths eg 7k versus 4k no handicap is given. Is this to do with individual player settings not allowing handicaps?

If the games aren’t being created as per the tournament specs, it’s basically a bug … even if “player preference” were being taken into account (which would be rather odd) that’d still be a bug.

We can @dexonsmith this topic in hopes he’s in a position to take a look … otherwise it is likely to be a bug in the queue for a while.

Might it be because of where the bars have been set? There would be no handicap for those who are above the bar. And the bars are by default at somewhat odd places on OGS if I recall correctly.
And actually I don’t even know how the second bar works as I’m only familiar with MacMahon with one bar only.

If I found the right tournament I see the bars are 10k and 20k, which I think is the default setting.
So I would expect everyone above 10k to play even games and everyone below to have handicap minus one. Not sure what happens after 20k!

So I think that it’s likely happening according to the OGS tournament specs, but these are not what one would expect from a “MacMahon” tournament in any other context!

Maybe tournament expert @Feijoa can shed some light?


yes you are right. all players on 10kyu and above play without handicaps. But this means that a 15 kyu player playing a 7kyu player doesn’t get a handicap. Given that it is a small group with 4-dan to 17kyu players I’ve suggested just one bar at 3 kyu for future MacMahon tournaments. Meanwhile, I’ve advised stronger players to give the requisite number of passes at the beginning of each game

So wait handicaps are now counted based on macmahon scores? When did that change?

I always thought ogs counts the handicaps directly from the ranks, while tournament tables do not affect the handicaps in any way.
This has been actually quite annoying for some tournament organisers as the more common way is to use the macmahon scores for calculating handicaps between players.

I think generally for ranked games I wouldn’t advise this, and usually tournaments are ranked games. Essentially if a 7kyu beats a 1d in an “even” game but the 1d passes 6 or 7 times to give a handicap, the system doesn’t take into account these passes and just scores it like a win in an even game.

I guess in one particular tournament it doesn’t really matter, but just more generally as advice say, the ranking calculations won’t be what you expect.


thanks for the advice. As this is a 3 round tournament and we are in the second round it should not cause much disturbance in rankings to people with several hundred games on OGS. Clearly, people new to OGS may experience some perturbations!

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Right now it doesn’t, but hopefully the v6 ratings update will as a consequence of more flexibly accounting for reverse komi and handicap in rating calculations

Is there any reason to expect that a ratings update would look at the game moves rather than settings to see if there’s something akin to a handicap?

What? Why would the game moves have anything to do with it? It’s still the game settings

Yes exactly. If the game settings say no handicap then there’s how it will be rated no matter how many passes one player makes at the start…


Do Mcmahon Tournaments implement auto handicap as forced passes?

No but maybe I’m now confused as to what you were talking about!

The tournament we were talking about was auto handicap but with a bar set too low so some games above the bar were not handicap when they were intended to be. The workaround was for the stronger player to pass however many times to replace the handicap. The problem with doing this is that the rating system doesn’t know that it’s being played as a handicap game so will not be correct for the outcome of that game.
Then you said

Seeming to say that the V6 will somehow detect initial passes and rate “correctly” as a handicap game even though the game is not a handicap game (as far as the system is concerned)

But that is not the case. But I now don’t think that’s what you actually meant. But it’s late now and I’m tired so hopefully it’ll all be figured out by the morning!

Oh, I missed this part. That seems foolhardy to do in a ranked game; I’m not sure why anyone would