If Mitsuko Uchida’s flyaway mane, gauzy fashion choices, and interviews spiked with whinnying Zen non sequiturs suggest preciously managed affectation, her artistry on the job reveals the prismatic, probing mind of a true explorer. Rather than strive for timeless “answers,” she stays in the moment, never stepping into the same river twice. Especially in the worlds within worlds of the great Schubert piano sonatas, Uchida might be the Emily Dickinson of the keyboard. Six of those sonatas (two programs of three) make up the repertoire for an autumn tour, with stops in Stuttgart, Dresden, Cleveland, and Lucerne. —M.G.