Chiroplast

A chiroplast is an instrument to guide the hands and fingers of pupils in playing on the piano, invented and patented by Johann Bernhard Logier in 1814.

[1][2] The instrument was a device that placed the wrist, thumb and fingers of a hand above five consecutive white keys of a keyboard, to overcome the difficulty of retaining their proper position by beginners.

[5] In 1822, Logier was invited by the Prussian government to Germany to set up a school instructing teachers on how to teach the use of the device in the country.

[2] The user passed their wrists through two parallel wooden bars,[2] which kept the hands at the correct distance from the keys.

[6] Each finger-guide was also attached to a stiff brass wire with a regulating screw, which kept the wrist in the proper position relative to the arm.