English Chess Forum

https://chess-results.com/tnr1064297.as ... ES&flag=30

Yes, I realise it's a bit late to mention it, but I was struck by the pairings in the last round of the Open. Running a 9-round Swiss for 16 players will throw up some anomalies, especially as there have been four byes. Joint leaders with one round to go are Eduardas Rozentalis and Georg Mohr on 6.5/8. Mohr lost to Rozentalis and drew with Koby Kalavannan, Rozentalis drew with Katarzyna Toma, Jack Rudd and Keith Arkell.

Tomorrow, we have
Keith Flanagan (1) vs ER (6.5)
Georg Mohr (6.5) vs Keith Arkell (4.5)

Keith F obviously entered the open to get tough opposition, so I hope he's pleased with the opportunity to play ER! I'm certainly not suggesting the pairings are wrong, but it does look a bit weird.

I assume it is computerised pairings and must be correct, and completing such a pairing the old-fashioned way, manually using pairing cards would be a nightmare with so many players having already played each other.

Has anyone an explanation for this unusual pairing ?

I once competed in an 11-round Swiss which had only about 18 players, and a similar spread of abilities to this Jersey one. And yes, there were a lot of unavoidable mismatches (my last-round opponent had a score about 3 points below mine). But even so, that Flanagan-Rozentalis pairing doesn't look right to me.

I have come up with one: it's a quirk in the FIDE pairing rules. Pairings that would give a player three of the same colour in a row, or a colour imbalance of 3 or more, are normally absolutely forbidden. But they're allowed in the last round, provided one of the players in the pairing is on over 50%. Now Flanagan has played nearly everyone on 4 or less, and the only one he hasn't, Clarke, is forbidden by those colour rules. So he has to hunt into the top half for opponents.

Similarly, the top half pairs absolutely perfectly except for Rozentalis, who has played everybody else on 4½ or more. So the top half minus him pairs normally - and then he's left over and is the only person left to play Flanagan.

I had got as far as wondering why Flanagan could not be paired against Clarke, and pondering if it was a colour issue (seeing that Flanagan had a third White in row). But Jack has clearly explained what I was inching towards. An interesting pairings quirk.

I do like the fact that the pairing algorithm rejected a pairing because it would have given a player three whites in a row, and instead chose a different pairing that gave the same player three whites in a row. A brilliant example of rules getting in the way of principles they're meant to be in the service of.

Can you see an alternative set of pairings that would be 'better'?

The alternative pairing I had in mind was boards 2-4 as per the computer, plus Waddington-Rozentalis, Gurner-Mihevc Mohr, Brixel-Strade, Waterfield-Rudd and Flanagan-Clarke.

Keith F did not get a shock result - I just hope he was pleased to play a strong opponent. The Holiday section had a fighting last round - every game was decisive.

IM Jack Rudd wrote: ↑

Sat Apr 12, 2025 8:06 am

The alternative pairing I had in mind was boards 2-4 as per the computer, plus Waddington-Rozentalis, Gurner-Mihevc Mohr, Brixel-Strade, Waterfield-Rudd and Flanagan-Clarke.

It sounds like the rule about three colours in a row only being allowed if one of the players is on more than 50% was designed to prevent a player in contention for 1st place or top prizes being disadvantaged or advantaged by three Blacks or three Whites or similar imbalance.

But the rule was poorly phrased.

So you should preference the top half pairing being more 'correct' than the bottom half pairing, because the top half pairing is more important to get correct. That way you get Waddington-Rozentalis and Flanagan-Clarke instead of Flanagan-Rozentalis and Waterfield-Clarke.

That last-round, top-board pairing in an Open tournament of a rating difference of 873 points is likely to be a record and hard to beat (someone will probably now go and find an example of an unrated junior prodigy winning an Open somewhere).

Christopher Kreuzer wrote: ↑

Sat Apr 12, 2025 2:47 pm

That last-round, top-board pairing in an Open tournament of a rating difference of 873 points is likely to be a record and hard to beat (someone will probably now go and find an example of an unrated junior prodigy winning an Open somewhere).

The pairings of Frederick Gordon in the September 2021 4NCL Congress come close.

https://archive.chess-results.com/tnr57 ... =30&snr=67

By virtue of being the lowest rated player he also got a round 1 bye.