Saturday, the Kentucky Derby will begin when they turn off the electricity, a maneuver that lets the magnetized starting gates fly open. In the next few seconds, 20 Derby riders will begin making quick, important judgments about how soon to commit their steeds to the battle for the favored locations up front where, in a 20-horse field, there is less debris.

This morning on the backstretch, they were talking about the importance in this chock-full race of getting to the first first, or at least in company with the frontrunners."They're going to hang up some runners on that fractions board," predicted Chick Lang, the Preakness operative who is on the Derby scene.

Translated, Lang's race-track idiom means simply: certain ones, including Proud Appeal, the favorite, Cure the Blues and the swift Californian, Bold Ego, would be high-tailing it out of the gate, not only to avoid early trouble in a 20-horse stampede but also to escape the clutter and mine-field possibilities in the stretch. Fractional times for the first two furlongs would make clockers blink.

One of those who isn't cut out to contest for the early lead is Pleasant Colony, the Wood Memorial winner who specializes in coming from behind. He will probably be the second choice Saturday despite risking destruction in the stretch. Not many opposed him in the Wood, where he found clear sailing.

Cure the Blues is the prevailing puzzlement of Derby Week. Three weeks ago, the then-unbeaten colt would have been the one to lick Saturday. Even the nose decision he later lost to Proud Appeal in the mile of the Gotham did not affect his status as pre-Derby favorite. But when he folded after a mile in the Wood and staggered home third, eight lengths out of it, it was dumbfounding.

There are still some Cure the Blues partisans who insists that so dreadful was his last race it deserves to be thrown out of all reckoning -- uncharacteristic of a colt who had shown every quality of a Derby-distance champion. So incredible was his performance in the Wood that one still-loyal Blues fan takes comfort in recalling an ancient race-track proverb: "If you can't believe what you saw, go back to believing what you believe before you saw it."

There has been a significant jockey switch by Cure the Blues' trainer, LeRoy Jolley, and heartily agreed to by owner Bert Firestone. This seems to say that Jorge Velasquez was being blamed for some of what happened to the Blues in the Wood, when he allowed Angel Cordero, on the longshot Noble Nashua, to hustle him through a sizzling six furlongs that left them both cooked.

In the last three-eighths, the stylish Cure the Blues lost his good action, and later it was discovered he had struck himself on the left hock during the race. At Churchill Downs, he has been working very well with a protective leather patch he will wear on Derby day, but he most important correction could be the change of riders.

The new rider is Bill Shoemaker, who, as it happened, was available. Knowingly or otherwise, Jolley is taking the advice of the esteemed Frank Whiteley who once dumped Ron Turcotte as the rider of Damascus with the simple explanation, "If you can get a Shoemaker, you don't ride a Turcotte."

It was in the late 1940s that a young California riding senasation named Bill Shoemaker was brought to Maryland to ride in a match race with the young Eastern phenom, Joe Culmone. Shoe won that race, which is incidental to Humphrey Finney's comment before it of the Shoe, "That boy will be around for 40 years. He is a beautifully porportioned small athlete with a marvelous ability to sit still on a horse."

Shoemaker has been around now for 35 of those 40 years.If an imputed ability to sit still on a horse seems to be an odd compliment, it isn't. Highly active riders are rarely in synch with a horse's movements or desires. Often they interfere with a horse's own actions, which are important to an animal. Somewhere back there, Shoemaker seemed to sense this.

Off his folderoo in the Wood, it would appear that Cure the Blues needs to be rated to conserve some of that swiftness he takes onto a track. Can the Blues be rated? The question was put to one horseman today. He said, "Cure the Blues is a big, strong, powerful colt, and free-willed. But he won't fight you if you try to rate him. For this, Shoemaker was an excellent choice."

With his sit-still tactics on a horse, Shoemaker is making no effort to offer a study in still life on the race track. He is communicating, telling his mount there's time yet, offering assurance. And giving his horse a needed breather in the backstretch. But, when necessary, Shoe has been known to go to the whip, a vigorous tactic he has sometimes used to win more races than any man alive. His reputation is secure. For Cure the Blues, the truth is nigh.