What is the difference between hermeneutics and deconstruction? This essay provides an answer by following the guiding thread of understanding that was already brought to the fore in Paris during the "improbable debate" between Gadamer and Derrida. Maybe there was and still is a "dialogue" between the two most important currents of continental philosophy, as Derrida suggests in his talk commemorating Gadamer at Heidelberg in 2002. It is a dialogue that passes through poetry, and above all the poems of Celan. In this way, the distance or the proximity between hermeneutics and deconstruction rests in the meaning of understanding: the one beginning from the uninterrupted dialogue, the other from the difference of interruption. Through a phenomenology of saying and of understanding, this essay asks at the same time how the differences of deconstruction are the stars necessary for the constellation of hermeneutics, and how the constellation is nevertheless necessary for every new star. It is perhaps the Schibboleth of Celan that indicates the point of orientation.