Organ shoes

Organ shoes are shoes worn by organists, designed to facilitate playing of the organ pedal keyboard. Also, since organ shoes are worn only at the organ, the use of special footwear avoids picking up grit or grime that could scar or stain the pedal keys. Shoes are not always used, some famous organists like Rhoda Scott play with bare feet.

Organ shoes are typically as narrow as comfortably possible, so as to prevent accidental playing of more than one pedal key at a time. They usually have both leather soles and leather heels that are glued into place (rather than stitched), which allow the organist to slide the feet along and across the pedals easily. The soles should be thin enough to feel the pedal key surfaces reasonably easily. Organ shoes typically have a slightly higher heel of about one inch - to ease playing with the heel, and to allow non-adjacent notes to be played at once by one foot.

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Wikipedia