The Puissance course starts off routinely. There are a few jumps, with one more difficult than the rest. Horses up to the challenge probably will finish without knocking down a fence.

The field is whittled away when wooden blocks or bricks are added to "the wall," making it three to six inches higher each time. As the wall gets higher, up to seven feet or more, horses no longer see an obstacle like others they have faced in numerous jumper classes. It's more like a building; there is no view of the other side.

The event draws the largest crowds, inspires the loudest cheers and the biggest nail-biter of the dozens of classes at the Washington International Horse Show.

The $15,000 Puissance will be held tonight at Capital Centre, where the indoor Puissance record was set in 1983, when Anthony D'Ambrosio rode Sweet N' Low over the 7-foot-7 1/2 fence.

"Last year I really felt like Daydream could have" broke the record, said Margie Goldstein of Flemington, N.J., referring to the horse she rode to a first-place tie at 7-2 but missed at the record height. "I felt that if I got another foot or two closer to the fence {before jumping} I could have made it. It has to be a very brave horse with a lot of jumping ability."

They key to success in a Puissance -- there are only a few each year in the United States -- is a bold, confident horse that trusts the rider and doesn't hesitate, Goldstein said.

"It's just a very different type of class that depends a lot on how the horse is feeling. It has to be trusting and have a lot of heart," she said. "Once the wall is over 6 1/2 feet . . . they really can't see where they are landing. You just try to ride them down {the stretch before the jump} as strong and confident as you can."

Building up that confidence sometimes takes a little animal psychology. D'Ambrosio, of Mount Kisco, N.Y., held Sweet N Low back in his first Puissance appearance. In 1982 he easily jumped a 7-1 fence at Capital Centre, but D'Ambrosio settled for third place rather than to attempt a greater height.

"I thought that was enough to ask a horse in his first Puissance," D'Ambrosio said. "I did not want to take the chance of having his good experience be spoiled. He did not have experience to jump record height. In that instance you cannot let your ego or desire to win {dictate} whether you go on."

Goldstein's strategy was the same when she held Daydream back from advancing in the event in 1988, the year before their victory.

"Sometimes you want to reward the horse for jumping so well," she said. "Daydream was feeling really in tune for a young horse that had never been in a Puissance. I wanted to leave him with a good experience. That proved to be successful, because he did win three classes after that."

David Raposa, of Clinton, N.Y., a member of the U.S. team this week, decided not to compete tonight because he and Seven Wonder competed in a grueling three-round Bank of Montreal Nations' Cup until late Thursday night.

"He jumped three rounds and I want to keep him fresh for Sunday's grand prix," Raposa said.

D'Ambrosio agreed that pushing the horse too hard is no good for this competition. "It is a difficult class and I don't want to enter anything that's marginal," he said. "I enjoy watching a good Puissance and competing in it as long as a horse is not asked to do something he can't do well. As long as the horse is not struggling."

Knowing when to stop can be tricky but comes from a strong relationship between horse and rider.

For Raposa, a horse's limit often is very easy to judge. "When you hit the wall, that's it. Or if the horse clears it and it feels so scary that you don't want to come back."