Laden with a library of booklets and magazines to aid me in making some sense out of the U.S. Open Championship Horse Trials. I made my way up the dusty trail to the Polo Grounds of the Myopia Hunt Club in Hamilton.

A pervading aura of manure seemed to guard the show grounds protectively, beckoning those familiar with its odor to come inside but warding off those not accustomed to it. I likened it to some delicacy peculiarly palatable to high society and rather than show my colors. I spent the day sniffing away as though I were savoring the bouquet of a fine brandy.

Still sniffing, I confidently entered the arena, and no one was the wiser as to my blissful ignorance of horses. Head down, scrupulously scouting the path before me for any deposits I could easily avoid, I ventured onward. First, a tour de stade: those continental expressions go so well with the equine scene.

"Excuse me." A chilly command from above froze me in my tracks. I had wandered smack into the path of a chestnut gelding and its charming 12-year-old rider, who was pert in her manner, precise in her dress and, in my opinion, a pain in the ass. I mustered up a feeble apology and let her trot by. The manure be damned: I raised my eyes and strode straight ahead.

Lacoste shirts and Villager dresses dominated the gallery, while riders decked out in the L.L. Bean's sporting look (or its equestrian equivalent) wore the healthy tans of leisure.

Groves of pines and evergreens outlined the expansive terrain of the polo grounds and little white picket fences defined the performing areas for the riders.

The three-day event was first introduced at the Olympics in 1912 under the name "The Military." The first day is the Dressage test which challenges the rider and horse to perform a series of some 20 tricky maneuvers, "to show the horse is calm and precise on the parade ground."

The second day is the Speed, Endurance and Cross Country event. It is defined to show "that the horse and rider could cross any terrain and surmount any obstacle to carry a message or scout a position." And while this cross-country steeplechase event is the most heavily weighted aspect of the competition, it is the final day's stadium jumping that draws the crowds.

The object of the stadium jumping is simply "to prove that on the day after a severe test of endurance, horses have retained the suppleness, energy and obedience necessary for them to continue in service."

By the time I arrived, Great Britain's Mark Phillips had already ridden. I was crushed. It was like going to a rock concert late and finding out the band had opened with one of the two songs you knew and liked. Princess Anne was to ride in another hour, though, so all was not lost.

The horse that everyone was focusing on was going through a series of trots and halts. I fumbled through my Ledyard '75 (the official name of the trials) handbook: move number 14, "serpentine three loops, the first and third true canter, the second counter-canter." Counter-canter, I thought sort of a ring to it, but what does it mean?

I continued my wanderings through a kaleidoscope of red, blue, green and black riding jackets. Exquisitely coiffured equines responded precisely to the gentle guidance of their riders' reins. Braided manes and brushed tails were only fitting for horses bearing names like Marcus Aurelius, Royal Core or Her Majesty's Arthur of Troy.

I continued past a row of concession stands run by the American Legion to the members only section of the bleachers. Here was the official luncheon spot for the habitues. Surrounding umbrella-shaded tables and a buffet line of noontime snacks such as beel bourgignon was a crescent of international flags. Ah, such tradition. I grabbed a hot dog and a beer from the American Legion and headed back to the horses.

I returned to the crowd of craning necks and clicking shutters just in time to see Princess Anne parade before the colonists. Her performance seemed relatively good with the exception of two mistakes accented by ooohs and ahhhs from the audience.

Despite what the purists may claim, the Princess and her husband, Mark Phillips, were strong crowd pleasers. Both are world class riders; Princess Anne won the European Championships in 1971, and Phillips is a goldmedal-winning Olympian. Early that morning. Phillips had marched his bay gelding, Laureat II, right into the lead of the Dressage competition.