The adjective that comes to mind again and again listening to pianist and composer Kris Davis’ quartet recording The Slightest Shift is “refreshing”. Much of the album sounds close to free improvisation, but there is also a recurring sense that one is listening to a modern chamber music ensemble. And the initial impression of at times decentralized free play belies a group working in close coordination within definite compositional frameworks. Tony Malaby (tenor saxophone), Eivind Opsvik (bass) and the bandleader’s husband Jeff Davis (drums) make up the quartet. The Slightest Shift is also a reminder that improvisation that pushes at the boundaries of form The opening “Bloodwine” is the first of several standout tracks. Its halting beginning gives way to a slow, swaying two-chord progression with a wide-ranging Malaby solo and Davis building increasingly tempestuous and dark chords beneath him. “Morning Stretches” is gentle and spare with, as the title suggests, a preparatory feel to it and segues into the album’s compositional highlight, the gorgeous “Jack’s Song”. Similarly, “Twice Escaped” begins sparely, becomes increasingly layered and arrives at a solo piano coda that segues directly into the rhythmically complex and kinetic title track.