The classic piano trio has a long tradition. The piano-drums duo has a tradition, too, but it runs less deep. Reasons of bridging timbres and melodies and rhythms account for some of that. However, so do the burdens placed on the players, who must account for that missing gel, and the listener, who has to listen a little harder to follow the dialog. Then again, there is nothing wrong with a close, concerted listen.

On Out of Athens, Greco-Bostonian Pandelis Karayorgis and Hellene George Kokkinaris come together to offer 13 tracks of dialogical free jazz, informed by classical elements. The album, however, is a tough one to pin-point. A few tracks — Sandbar, Erasures, and Thoroughgoing Lines — are jumpy Karayorgis compositions. A couple tracks are piano and bass solos, but the rest seem to be improvisations. If that is so, these musicians display a surprising degree of sympatico. At no point does Kokkinaris sound out of place plucking along with Karayorgis, who sounds like a modernized combination of greats such as Cecil Taylor, Art Tatum, and Thelonius Monk in his odd melodicism, and like Joel Futterman in his skillful ribboning of various jazz and adjacent styles. Kokkinaris, meanwhile, unleashes in a measured way. Rarely does he go on a tear and the strongest moments when he does tend to be with his bow. Maybe it is precision rather than gusto, but his pizzicato sounds taut like another element of Karayorgis' punctuated piano.

Through it all, Karayorgis remains the prime mover. His keys shape the flow and Kokkinaris, admittedly younger and engaging in a vernacular that is not his primary, usually responds and follows, or simply but quite skillfully fills out the sonic space around the piano. At moments when the lead is more balanced, such as in "Argle-Bargle", the divergence in styles becomes clearest. Even here, however, the first three minutes seem a negotiation and the remaining two-and-a-half find their common, or rather uncommon, stride following a torqued piano melody. A different and absorbing take on an unconventional duo.