"Play Bach" is the name of Eliot Feld's effervescent, ingenious and engaging new ballet, given its Washington premiere last night at the Kennedy Center as the Feld Ballet settled into the Opera House for two weeks of performances. The troupe of 23 dancers, seen here a year ago, has lost a few members and gained some, but in any case seems to be bracingly fit all around and dancing with the kind of thoroughbred e'lan that is characteristic of the Feld at its best.

The title of the new opus tells much about the spirit in which Feld approached the music--the B-Flat Major and G Major Partitas, Nos. 1 and 5 (minus the Minuet of the former), by J.S. Bach, as capably played in the pit by staff pianist Peter Longiaru. The costumes by Stanley Simmons--white formfits, resembling "longies" underwear, with color-accented elbow and knee guards--carry the suggestion further. The music of Bach has touched many different responsive chords in our era, underscoring its potential affinities with everything from electronic synthesizers to improvisatory jazz. For Feld, these Partitas, consisting mostly of stylized social dance forms like the saraband and gigue, provide a fittingly ebullient rhythmic pretext for an intricately playful ballet. The imagery, though, is more gymnastic and calisthenic than overtly athletic. The ambiance seems closer to Vic Tanny than to the Rose Bowl.

The piece abounds in typical Feld dance witticisms, but the jokes all grow out of the choreographic material and illuminate it in some essential way. The very first movement, to the opening Prelude of the B Flat Partita, brings us five women standing in a classic diagonal lineup. Among the movements they initiate is the old childhood test of the ability to carry out two separate actions at once--patting the head and rubbing the tummy, simultaneously. In the framework of this music, the twin gesturing becomes a funny metaphor for Bach's counterpoint--two (or more) melodies going their own way but in coordinated fashion. As the movement proceeds, the analogy is carried further still, when what began as unison behavior goes out of phase, so that each still does the same thing but at different points in time, exactly like Bach's melodic imitations.

Not everything in the piece is as explicitly referential as this, but the notion of the choreography as contemporary commentary on and application of Bach's esthetics holds good throughout. The entire B Flat Partita is danced by women, until the concluding section, which gradually introduces the men; the G Major Partita features both sexes (16 dancers in all), and in keeping with the musical character, becomes even more physically flamboyant. A series of characteristic images--arms rolling over one another like eggbeaters, legs pedaling in the air from a recumbent position, sinuously jiggling shoulders--not only bestow unity and identity on the individual sections of the dance, but also recur in a cumulative way at two highpoints--the slow Saraband of the G Major Partita, which is the most spellbinding part of the ballet, and the final, kitchen-sink Gigue that ends the work as a whole. In the Saraband, the recurring images and some new ones--such as a seated couple linked hand and foot and rocking to and fro like a rowing machine--are all executed in slow motion, to a completely transporting effect. The Gigue masses all the dancers on stage at once in a recapitulation of the ballet's prime motifs--reeling arms and wheeling legs and everything else going gangbusters.

"Play Bach" is exciting, clever, diverting and, at times, awesomely imaginative, yet the ballet in toto seems skin-deep, sticking pretty much to the brisk kinetic surface of the music and bypassing many of its subtler qualities. The rest of the program, containing three older, familiar Feld pieces--the frisky, companionable "Harbinger," the idyllic "The Gods Amused," and the darkly expressionistic "At Midnight"--showed us other sides of the choreographer's nature. In particular, "At Midnight," with its Tudoresque eloquence of gesture and shape, remains one of Feld's most compelling ballets and one of the most satisfying realizations in dance of the fateful musical universe of Gustav Mahler.

Ten more Feld ballets, ranging over his 15 years as one of America's most individual dance makers, will be seen in the course of the troupe's engagement, its longest thus far in Washington.