Rückpositiv
Organ division positioned behind the organist's back.
What it means
The Rückpositiv (chair organ, or positive-in-the-back) is a self-contained division of an organ with its own set of pipes and wind supply, placed not in the main case but physically separate, behind the organist's back, usually at the railing of the organ gallery.
Musical use
Historically, the Rückpositiv was especially common in north German and Dutch organs of the 16th to 18th centuries, serving as an independent manual division with a characteristically transparent, direct sound that projects straight out to listeners in the church. It is distinct from the Great and the Swell divisions, both of which sit inside the main organ case: only the Rückpositiv stands physically separate behind the player, producing its own immediate, spatially distinct sound.
Performance practice
Use the Rückpositiv deliberately for solo, clearly contoured stops, since its direct sound stands out noticeably in the room from the fuller Great division.