When all seven Variety Groups are done, it is time for Best in Show competition. Before that happens, there may be some additional exhibits in the big ring. There may be a competition for Best Brace in Show, or the best Junior Handler may be allowed to strut his dog. Some shows may have Puppy Group competitions (held in another ring while Variety Group competition is taking place) and Best Puppy in Show. There might be a competition as well for Best Bred-by-Exhibitor dog. None of these "count" as far as the actual competition of the day is concerned.
The climax of any show is for the top dog, the only dog that day going undefeated. In a single-breed specialty show, the Best of Breed dog is also the Best in Show dog. In a competition limited to a single Variety Group, the dog which is first in the group is the Best in Show dog.
In an all-breed show, the final competition of the day is among the seven Variety Group winners. There is a single Best in Show judge. I sometimes get asked why a panel of judges isn't used. Quite simply, it would be too difficult and time consuming. One year in the 1920's, the Westminster KC tried a three-judge panel. It took them an hour and a half to make up their minds. Probably it wasn't the best dog but the least bad one there that day that won.
The Best in Show judge has been judging breeds and groups that day. Westminster is unique in having a set of judges who do only the breeds, a set to do only the Variety Groups, and a judge whose sole job is to do Best in Show. This judge is licensed to do at least one of the seven Variety Groups. Most judges doing Best in Show are licensed to do more than one group.
The four placement standards are removed from the ring, since only one dog will win. In Europe they have a Reserve Best in Show, an idea that thankfully hasn't percolated to this side of the pond.
(Parenthetical aside: notice how American sports like basketball, baseball, and football are played until there's a winner while sports not original to the U.S. like soccer, cricket, and hockey allow for ties?)
The Chief Ring Steward calls all the Variety Group winners into the ring. As before, the judging follows the pattern seen in the Breed and Group competitions, even though the judge may have already seen the dog once or twice before that day. The dogs are examined standing and their movement is observed both on the down-and-back and from the side. When the judge has finished examining the dogs, he'll ask them to go around individually, always to the applause of the spectators at ringside.
He will then go over to the table by the side of the ring and note in the judge's book the armband number of his choice, sign the book and note the time, then pick up the big red, white, and blue Best-in-Show ribbon, of which there's only one. The Show Chairman will also come into the ring with the Best-in-Show trophy. He will then walk toward the middle of the ring toward the seven finalists and announce his choice. Applause from ringside and a happy winner accepts the handshakes of his final competitors. The dog, of course, is overjoyed too and will dance around telling his handler, "We did it!"
The day is done. Hundreds, perhaps thousands of dogs have competed today but only one is Best in Show. Who are they? To begin with, Best in Show dogs are almost always champions of record already. I've written to the AKC to ask when the last time a class (non-champion) dog went Best in Show. I never received an answer (typical), but something from my dim distant memory tells me that a Fox Terrier handled by Ric Chashoudian did it at a show I was at in Bryan, Texas in the mid-1990's. That may say more about the handler than the dog, however.
Some dogs compile extraordinary numbers of Best in Show wins. The German Shepherd Dog Ch. Altana's Mystique, owned by Jane Firestone and handled by James Moses, won 257 Best in Shows, which may the record. She was never bred. The Afghan Hound bitch Ch. Tryst of Grandeur, handled by Michael Canalizo, won 161 Best in Shows, 432 Group 1's, and 557 Best of Breed awards.
I've never done a study of it, but my guess is that in any given year a lot, if not most Best in Show wins are taken by a relatively small number of dogs. What it takes to keep a top dog on top will be the subject of a future installment.