Waikato-Bays Main Centre Swiss Pairs

This event took place in Hamilton on Saturday 12th of September. It is rare to see a room so jam-packed full of Grand Masters - 58 at a rough count. Fifty pairs had entered and the format was six 12-board matches under director Tony Morcom's guidance.

The eventual winners with six straight wins were Michael Whibley and Steve Baron, with Herman Yuan and Yuzhong Chen runners-up. These two pairs, well clear of the field, met in the last match of the day. Had the local pair managed a 17-13 win the top placings would have been reversed. Full detail can be found here.

Of interest to some was mention of a couple of scoring techniques said to make outcomes of Swiss Pairs less prone to the vagaries of who gets which cards. The field may be divided so that one half is always seated N/S and the other E/W. This method has been used at the Gold Coast Congress for some time and has obviously found favour.

The other method is called Cross-IMP scoring which involves each pair's score on a board is imp'd against every other pair (as opposed to the average score of all other pairs in datum scoring).

You can Google "cross imps scoring bridge" to find much interesting discussion on this topic. Basically, it damps down much of any “wildness”. A typical data sheet would look like this:

(hold down CTRL and roll the scroll wheel on your mouse to zoom in if you can't read it)

Michael /Geo’s 230 on board 13 has been “IMP’d” against all the 25 other scores on this board. It’s not as good as the 620 that EW got at table 1 (means +9 IMPs to Gwyn/Kate) but better than the 110 EW got on table 2 (means -3 to Gwyn/Kate), way better than the 120 NS made on table 3 … etc etc. All these scores are averaged to give an IMP total of 4.4 to Michael/Geo on board 13. This contrasts with “imp-ing” the 230 score against a single datum figure calculated by averaging all eligible raw scores – possibly -90 in this example – to give an IMP score of -4.

You can re-score a set of final results in cross-IMPs. Don’t expect huge upheavals, though. You should allow that, using this slightly fairer way of scoring Swiss Pairs would mean slightly fairer draws throughout an event. This would build until the final placings may well have look quite different to ones run under the Butler datum method.

You can see such a sample event by comparing this with the link given above.