A fugato on the chorale 'Ach Gott, vom Himmel sieh darein' by Friedrich Wilhelm Zachau (1663-1712).
A meditation like piece on the melodic phrases of this hymn. At first played on the Oberposidiff (with Krumhoren 8' and Tremulant), repeated on the Rückpositiff with soft foundations, concluded on the Oberposidiff again.
Sounds (as much of this repertoire) great on the beautiful Stellwagen instrument (1655-1659) at Stralsund.