Few horse races in the world attract such a concentration of riding talent as the Washington, D.C. International.

The cast of characters in the 29th running of the classic Saturday is typical. America's Bill Shoemaker and Jorge Velasquez, France's Alfred Gibert and England's legendary Lester Piggott have months on some of the principal contenders. The annual presence of such stars as Laurel gives rise to a great riddle:

Why do jockeys so often ride with such staggering ineptitude in the International?

Celebrated riders habitually commit errors in this race that would be an embarrassment to a raw appretice at Charles Town. They do it so regularly in fact, that perhaps three times in the last six years the superior horse has failed to win the International.

Those of us who bet seriously on the favored Le Marmot last year are still haunted by the memory of Philippe Paquet's astonishing performance. It will live in infamy.

Paquet was unprepared for the start and spotted the field three or four lengths when the gate opened. Immediately he overreacted, gunning Le Marmot up on the outside into contention, and then dropping to the rail where his troubles began in earnest. At the moment he wanted to make his move he found himself trapped behind a wall of horses. He attempted to sneak through on the rail, couldn't make it, checked his mount, tried to get through again and checked again. By the time he found running room it was much too late. Paquet finished third on a horse who might have been five lengths the best.

The year before that, America's Jeffrey Fell blew the International on Tiller when he misjudged the pace woefully and kept his mount in last place while the leaders were crawling six furlongs in 1:14 1/5. This miscalculation was minor compared to Piggott's butchery in the 1974 International.

He was riding the magnificent filly Dahlia, who had captured the race the previous year with a breathtaking stretch run, and he clearly intended to duplicate the performance. But he kept Dahlia so far behind a slow pace -- trailing the leaders by eight lengths with a quarter of a mile to go -- that she could not possibly win. Dahlia unleashed one of the greatest stretch runs any racing fan will ever witness, covering the final quarter in 22 2/5 seconds, but because of Piggott's misjudgment she managed only to finish third.

Presumably, jockeys are not lobotomized before they come to Laurel to ride. Europeans are prone to error in the International because the race course at Laurel is so different from the ones they are accustomed to.

In Europe, horses customarily race in a tight pack until they turn into the final straightaway, which may extend for more than half a mile. Then the horses fan out and drive to the wire. But at Laurel, with the stretch only an eighth of a mile long, a jockey who waits until the final turn to make his move probably has cost himself the race.

The International should theoretically give an edge to American riders who are accustomed to competing on this country's more compact race tracks. But domestic riders have far less experience than Europeans with the tactical problems of 1 1/2-mile races. And a strange thing often happens to the Americans who compete in this event. They act as if they are obliged to play the European waiting game, and minimize the accent on speed that is the hallmark of our racing.

In 1974, jockey Ron Turcotte was riding Desert Vixen, the only speed horse in a field of plodders. Ordinarily a good jockey would try to open a comfortable lead and force his rivals to alter their usual tactics. Instead, Turcotte practically strangled the filly, going the first three quarters of a mile in a ridiculous 1:17 1/5, putting her only a length in front. With such a narrow advantage there was no way she was going to withstand the late surge of the European horses who are trained to put in one big burst of speed in the stretch.

In view of this aspect of the International's history bettors have to be wary. And I am especially wary, knowing that the probability of human error is the only thing that can mess up an otherwise sure-fire exacta wager in the 29th International. Details tomorrow.