About downfloats and upfloats

[Wadih Khoury]

As I understand it, (and simplifying a bit), when a point group has an odd number, generally the lowest seeeded is downfloated while the highest seeded of the next lowest point group is upfloated.

Does anyone know the reasoning behind this structure of swiss pairings?

I was musing that generally, the downfloated guy is often "punished" by playing someone much stronger. It is effectively giving the benefit of the draw to the lower group. Has Fide explored other ideas, like downfloating the player as the highest seed of the lower group and then just applying the normal top half vs lower half? Would that work or why not?

[IM Jack Rudd]

Almost anything would work, in the sense of producing reasonable pairings. (CAA unified pairings, for example, use "median down, top up" for short tournaments and "median down, median up" for long tournaments.)

In general, there is only one piece of advice I can give for testing this sort of thing: try it, and see how it works out.

[Roger de Coverly]

Has Fide explored other ideas, like downfloating the player as the highest seed of the lower group and then just applying the normal top half vs lower half? Would that work or why not?

I don't know about FIDE experiments but for many years, British arbiters followed a practice of floating the median player, the one in the middle of a score group. That also has a practical difference when there's a full point bye to be awarded, that it goes to a player in the middle rather than the tail. The FIDE method can have the unpleasant effect of awarding byes to same player in multiple tournaments. That's where the player is the lowest rated either just because they are repeatedly the weakest entrant, or by virtue of being unrated are treated as having a zero rating. FIDE breaks ties for ranking by alphabetic order.

[Richard Bates]

The FIDE approach has one theoretical benefit. In theory it reduces the possibility of multiple players winning tournaments with 100% scores in situations where the number of players is too large for this to be guaranteed in the number of rounds available. In all other cases the CAA approach is far superior. This is most obviously evident in the early rounds of tournaments when downfloats represent, rather than a tough game for the weakest player, actually a guaranteed and undeserved point -

[Wadih Khoury]

Almost anything would work, in the sense of producing reasonable pairings. (CAA unified pairings, for example, use "median down, top up" for short tournaments and "median down, median up" for long tournaments.)

Doesn't FIDE impose certain rules for pairings? At least at the top level?

[Alex McFarlane]

It does, but only fairly recently.

However, in theory, you can ask for your pairing system to be accepted. It was suggested that if the CAA method was computerised there was a fair chance that it would be. Unfortunately, the attempt to automate it failed to achieve the required level and was abandoned when the programmer lost interest.

FIDE from time to time does suggest that it might introduce the median of the score group as the player to get the bye.

There are a number of 'problems' with the FIDE system which the CAA one tried to avoid. The FIDE system (almost) always works down and ignores the actual rating. This means that if the pairing should be 5 v 23 but these players had already met, the FIDE system will look at 5 v 25 (assuming 24 is due white) and pair them rather than looking at 5 v 21 as well. The CAA system considers both options and chooses the one which minimises the rating difference. So even if 21 and 23 had the same rating the FIDE system would not swap the players. However, it is this that makes it so difficult to program.

If there are any programmers out there willing to give it a go ...

[Roger de Coverly]

Doesn't FIDE impose certain rules for pairings? At least at the top level?

I don't think FIDE have any concerns over pairing rules when accepting events for rating. British events using CAA rules or ranked with reference to national ratings have always been accepted for rating. Where FIDE seemingly do have concerns is when Norms are at stake. The Isle of Man Open had a novel idea of adding interest to the opening of the tournament and the first round by doing a random draw for some of the first round players. FIDE promptly banned the practice, presumably by disallowing Norms if the method was used.

There's another recent thread discussing FIDE's intent to make obtaining Norms more difficult.

[Ian Thompson]

The Isle of Man Open had a novel idea of adding interest to the opening of the tournament and the first round by doing a random draw for some of the first round players. FIDE promptly banned the practice, presumably by disallowing Norms if the method was used.

Did they ban it or just point out that it violated the existing rule 1.42g for obtaining norms ("Tournaments that make changes to favour one or more players ... shall be excluded.") which it clearly did if you interpret the rule to mean the consequence of an action rather than its intent.

I wonder what FIDE would make of an all-play-all tournament offering norms if it used the same pairings as this non-norm tournament -

NO PAIRINGS UNTIL THE BEGINNING OF THE ROUND!!

Avoid the stress of computer preparation!
You can relax: your opponent won’t come to the game with any foreknowledge of your opening preferences. An innocent hand will choose the round number out of a bag, seconds before the game.

[NickFaulks]

I wonder what FIDE would make of an all-play-all tournament offering norms if it used the same pairings as this non-norm tournament -

NO PAIRINGS UNTIL THE BEGINNING OF THE ROUND!!

Avoid the stress of computer preparation!
You can relax: your opponent won’t come to the game with any foreknowledge of your opening preferences. An innocent hand will choose the round number out of a bag, seconds before the game.

How on earth does that even work in a round robin?

[Ian Thompson]

I wonder what FIDE would make of an all-play-all tournament offering norms if it used the same pairings as this non-norm tournament -

NO PAIRINGS UNTIL THE BEGINNING OF THE ROUND!!

Avoid the stress of computer preparation!
You can relax: your opponent won’t come to the game with any foreknowledge of your opening preferences. An innocent hand will choose the round number out of a bag, seconds before the game.

How on earth does that even work in a round robin?

Obviously less effectively as the tournament progresses if the objective is for players not to know who they're about to play until the last moment.

I assume you take the Berger pairing table and then do a random draw to see which round number you play next just before a round starts.

[LawrenceCooper]

I wonder what FIDE would make of an all-play-all tournament offering norms if it used the same pairings as this non-norm tournament -

NO PAIRINGS UNTIL THE BEGINNING OF THE ROUND!!

Avoid the stress of computer preparation!
You can relax: your opponent won’t come to the game with any foreknowledge of your opening preferences. An innocent hand will choose the round number out of a bag, seconds before the game.

How on earth does that even work in a round robin?

I think it means that you have rounds 1-9 pairings done in advance but not published. Only announce which of the nine rounds pairings will be used for that round as the players arrive.

[NickFaulks]

I think it means that you have rounds 1-9 pairings done in advance but not published. Only announce which of the nine rounds pairings will be used for that round as the players arrive.

For diligent preparers, I think that will make matters worse rather than better. They will feel each evening that they have to prepare not just for one opponent, but for all those they have yet to play.

I also predict squeals from those who get four blacks in a row, which for some players is a very sore point.

[Roger de Coverly]

I think it means that you have rounds 1-9 pairings done in advance but not published. Only announce which of the nine rounds pairings will be used for that round as the players arrive.

Surely in an all play all of 10, you would know the other 9 opponents, so with sufficient time have something prepared for each of them regardless of the order in which you played them.

[LawrenceCooper]

I think it means that you have rounds 1-9 pairings done in advance but not published. Only announce which of the nine rounds pairings will be used for that round as the players arrive.

Surely in an all play all of 10, you would know the other 9 opponents, so with sufficient time have something prepared for each of them regardless of the order in which you played them.

Yes, it's hardly a foolproof plan and probably means some players may feel the need to prepare for every remaining opponent with both colours each night.

[Ian Thompson]

I think it means that you have rounds 1-9 pairings done in advance but not published. Only announce which of the nine rounds pairings will be used for that round as the players arrive.

Surely in an all play all of 10, you would know the other 9 opponents, so with sufficient time have something prepared for each of them regardless of the order in which you played them.

Yes, it's hardly a foolproof plan and probably means some players may feel the need to prepare for every remaining opponent with both colours each night.

There's an exercise for someone with nothing better to do on a Sunday afternoon. If the organisers didn't disclose each player's pairing number, nor which round numbers were being played each round, how many rounds would it take for players to work out all the pairing numbers, and, from that, the colour they would get against each remaining opponent?