Miles Davis's most successful groups--his first great quintet with John Coltrane, for example, and his mid-1960s outfit with saxophonist Wayne Shorter--are well known, but the ensembles in-between are also notable. On this 1964 concert, recorded in Tokyo, Japan, Miles was already working with the rhythm section he would maintain until 1970--drummer Tony Williams, bassist Ron Carter, and pianist Herbie Hancock. The saxophonist, remarkably enough, is subsequent avant-garde legend Sam Rivers. Rivers is a unique and under-appreciated player not bound by stylistic constraints; he plays with great verve, humor, and invention. Though Rivers seems a bit out of place on this set of mostly standards (which includes "My Funny Valentine" and "All of You"), it is interesting to hear how his sound changes the group, pushing it toward more flexible rhythmic and harmonic structures. "So What," for example, grows to skittering near-cacophony, with a series of complex solos. Hancock's blinding right hand and the propulsive rhythms of Carter and Williams also drive Davis to some of the edgiest playing of his career at that point. MILES IN TOKYO is a fascinating document of Davis in transition, but is also worth picking up for the chance to hear Rivers in such unique company.