VERY FEW rock groups, and even fewer American ones, manage to make music that is not only complex in its musical structure but at the same time retains the visceral, frantic dynamism that one associates with true rock&roll. The Bead Game is one of the finest rock-groups in he country precisely because its music is just such an extraordinary synthesis of complexity and dynamics.

The members of The Bead Game all have a highly developed instinct for this sort of rock-kineticism. The drummer, Jimmy Hodder, always maintains a sharp edge to his drumming, which is in part a function of the extreme, pungent clarity of every one of his beats, the bassists (Lassie Sachs) consistently keeps up a furious fluttering, Bobby Gass, on organ, punctuates the music with gigantic, sudden, marching chords, constantly accenting with his left hand the lyrical melodies that he plays with his right. The lead-guitarist, John Sheldon, has the kind of rhythmic chording sense that is so conspicuously absent in most white American rock-guitarists. In addition there is a fifth instrumentalist in the group, Kenny Haag, who provides some extra syncopation on rhythm guitar or tambourine or whatever is at hand.

And equally the members of the Bead Game are consummate musicians all who have evolved for themselves an immensely satisfying and rich musical form. Kenny Haag writes all the songs and the members of the group then painstakingly arrange them, integrating elaborate variations on the basic tune and a dazzling array of individual musical parts to make a coherent fertile whole.

THE TYPICAL song begins with a soft organ intro which is then picked up by the others and transmuted through a series of structural and musical changes. For example, in "Punch and Judy" each member of the group does a solo (Lassie Sachs' bass solo being outstanding) while in the background the others play the melodic line in a fading spiralling version.

The Bead Game also has virtually mastered the art of switching from tempo to tempo. On "Slipping," the song begins with Jimmy Hodder singing in a slow 4/4, which then becomes a hard hammering instrumental break in 6/8 followed by a simmering and brilliant guitar bridge in fast 4/4 which leads back into the slow 4/4 with the vocalist coming back in. A few rounds later Hodder beings singing in the 6/8 tempo and the slower beat becomes an arena for long and reflective improvisational playing, completing the circle perfectly. Such fully realized, very abrupt changes, occur again and again in the Bead Game's music and serve to enhance the kinetics of the song by keeping the listener fresh and on his toes, and, surprisingly, also make wonderful musical sense.

The two principals, Gass on organ and Sheldon on guitar, are remarkable musicians. Bobby Gass, a Harvard senior, was classically trained and brings all the precision and subtlety of refined technique to the brash vitality of the rock-world which he seems also to have absorbed. He composed a fugue for "Lady," which goes so well with the traditions of rock&roll that it leaves one's faith in the future of contemporary music gloriously reaffirmed.

One realizes occasionally quite how unmusical a sound is produced by electric lead guitar--it consists of no more than a raw electronic note. A little mystifying to think that this particular sound is the supreme voice of rock-music. But suddenly, when Sheldon is playing, pulling out an insistent sizzling line of pure sound, polished and gleaming at the edges, like a stream of oozing silver liquid, everything begins to make sense and rock is redeemed as one of the most important artistic movements of out time.

There is so much more to say about the Bead Game, about Lassie Sach' driving bass runs, about Jimmy Hodder's soft and eloquent singing even while drumming, of Kenny Haag's hauntingly spiritual lyrics, but time and space run out.

The Bead Game's sudden emergence as a full-grown rock group of overwhelming intensity and power is like seeing a super-group grow up in your backyard. It would seem to be near-criminal to pass them up.