Jazz took over the Kennedy Center yesterday. For one day at least, the dancers hung up their shoes and the orchestra abandoned the stage as Washington opened its ears to America's classic music.

The choices were tough for the patrons of the Kool Jazz Festival since it was physically impossible to see every artist performing in every nook and cranny. The constant flow of pedestrian traffic suggested that many people were trying. "It helps to have the ears of an elephant and the legs of gazelle," said a normal-looking but obviously excited Rob Bush, who drove down from Cumberland.

"Programs, programs, get your programs!" There was a hint of baseball, bluegrass and rock festivals as well with T-shirt vendors hawking their wares (including a Leroy Neiman poster for $25) and patient fans waiting in slow lines for drinks and food (mostly candy) to help them overcome the travel fatigue of headlong plunges from one theater to the next. Like a ride on the proverbial A Train, it was as if after each performance the people on the platform and in the train switched places.

Those rushing from one concert to the next were likely to be waylaid by the tireless swing of the Dick Hyman Classic Jazz Band or the Savoy Sultans. These bands, featuring a healthy dollop of Dixieland clarinet or uptempo swing powered by trombone and trumpet, were so popular that they congested the hall with foot-tapping converts: Doc Cheatham's facile, driving horn belied his 70-plus years, while Vic Dickenson's droll trombone set permanent smiles on passing faces. Like the old smoothies at the Ice Capades, the veterans skated through familiar classics that yielded like soft ice under their blistering straight ahead solos.

Unsuspecting tourists could be excused for thinking they'd strayed onto the corner of Bourbon and 52nd Street in New Orleans.

The Kennedy Center was brimming with rabid fans (who must have felt this was a preview of dying and going to heaven) and with the curious who realized the 12-hour festival was the best jazz sampler they could ever find to experience old and new, eclectic and electric.

Torn between Miles Davis at one end of the Kennedy Center and Dizzy Gillespie at the other, Herb Wilson of Hyattsville, a veteran of many Newport Jazz Festivals, symbolized the dilemma: "When you say 12 o'clock for Miles and 12 for Dave Brubeck, you've got a tossup!" For the jazz die-hard, it was a test not only of decision making, but endurance, since the music went from noon to midnight.

It was certainly the largest collection of major jazz talent under one Washington roof; paraphrasing Steve Allen's comment about Pia Zadora during Radio City's "Night of 1,000 Stars," if a bomb had gone off, it would have been a big boost to Chuck Mangione's career. Like the audience, which seemed to encompass all colors and ages, the musicians spanned five decades of quality jazz with juxtapositions that seemed ordered by a higher force.

The most telling occurred in the afternoon session at the Eisenhower Theater when the future of jazz trumpet, 20-year-old Wynton Marsalis, met Dizzy Gillespie, the living symbol of that instrument's be-bop past. To add to the historic overtones, they were backed by the three-man rhythm section of the second great Miles Davis Quintet--pianist Herbie Hancock, bassist Ron Carter and drummer Tony Williams. While Davis' old mates grinned at Gillespie's sly tricks, Davis himself crouched in the Concert Hall with his back to the audience and led his newest young band in half-hour slices of electrified solos and funky rhythms.

Ironically, there was a slight delay for Davis' second concert so the waiting crowd was entertained by Panama Francis and the Savoy Sultans with the venerable "Moten's Swing." The Sultans filled the south lobby, their fiery solos resting upon hot ember riffs punctuated by the stomping beat of leader Francis. Howard Johnson's punchy alto sax line on "It Don't Mean a Thing If It Ain't Got That Swing" got the crowd swaying in the pre-summer sunshine and occasional breezes that poured in from the Potomac River side. Later, of course, it was "Stormy Weather."

The mood in the Kennedy Center was one of cautious exultation, with promoter George Wein confident that yesterday's event was only the first in an annual series of Washington concerts. "Everybody was on time for a 12 o'clock gig," he sighed with a triumphant air. Wein indicated that close to 9,000 tickets were sold for yesterday's event (preceded by a Concert Hall sellout the night before with Benny Goodman).

The normally staid Kennedy Center resembled both a flea market and a gigantic cocktail party: There was so much jazz, so many assorted flavors, antiques, treasures and discoveries that even a traffic cop might have forgotten which was left and which was right.

The day's hottest ticket was at the Eisenhower, with fans forming serpentine lines to see the Gillespie-Marsalis match-up.

Among the highlights:

* A genial gridlock in the South Foyer as a thousand fans emerging from the Concert Hall were stopped in their tracks by the high-speed, Rachmaninoff-cum-boogie, shimmy steps, high kicks and generally outrageous performance by pianist Dorothy Donegan.

* The Leroy Jenkins Mixed Quintet and the World Saxophone Quartet, two chamber groups playing without rhythm sections. Although usually labeled avant-garde jazz players, their reeds, violins and bass clarinets reflected a pastoral classical influence.

* Gillespie, the rotund elder statesman, and Marsalis, the slim, trim heir apparent, embracing at the side of the stage and sharing a private joke.

* Washington pianist John Eaton staring out into the crowd after performing pieces by Joplin, W.C. Handy and Carmichael and asking, "Any preferences? I'm used to working in cocktail lounges."

* Liquid, languid vocals from Sarah Vaughn, Shirley Horn, Carmen McRae and Betty Carter that frequently erupted into passionate scats and almost always brought new meanings to familiar lyrics and vibrant twists to familiar melodies.

* Young fans sitting crosslegged on the large black carpet of the Terrace Theater lobby as Washington saxophonists Ron Holloway and Marshall Keyes transfixed them with smooth mainstream bop.

All in all, it was a day to survive, as well as to remember. Next time around, maybe there will be some of the chop sessions that help define the urgency of jazz, some big bands, some of the better fusion groups.

Washington's first Kool Jazz Festival celebrated the acoustic side of invention for the most part; that probably helped turn a few ears to the fact that there are many outstanding musicians and clubs within easy reach. Things ended, appropriately 'round midnight.