A 10-part (German) alphabet-titled collection of bagatelles by alto saxophonist Anna Kaluza and bassist Jan Roder, Am Frankfurter Tor demonstrates their in-the-moment cohesion and instrumental blending. Kaluza, who is part of the Berlin Improvisers Orchestra and leads her own group and veteran journeyman Roder, best known for his membership in the Monk's Casino quartet, work out a simple strategy with the saxophonist's quicksilver trills and slithering tone variations wrapping around and stabilized by the bassist's sympathetic andante movements.

Not that this is just a series of reed exercise. Roder's arco and pizzicato facility create their own momentum when, for instance, he counters Kaluza's shaded peeps and lyrical puffs with concentrated stops on the jaunty "Vier" or when his squeaky sul tasto introduction to her flutter-tonguing on "Drei" is resolved with subsequent reed shading without strain as he encourages a lyrical narrative. Dedicated to exploring every nuance of timbral color from their respective instruments, Kaluza's output includes bites and snorts, as she emphasizes multiple notes in sequence. Meanwhile Roder's swift plucks and gritty bow slices keep up connective pressure, yet also mirror her expositions close enough to confirm arcadian story telling or dissonant asides.

Working up to the concluding "Zehn" quick in-and-out reed breaths and cascading string thumps are gradually replaced by a bugling interlude by Kaluza as Roder's more intense bass rebounds emphasize logical expression. Without resorting to dissonant slices or overblowing the duo cannily skirts sameness by letting their partnership emphasize sonic interchange.