Editing Recorder (musical instrument) (section)

==== Partial covering of holes ====
Partial covering of the holes is an essential part of the playing technique of all recorders. This is variously known as "leaking", "shading", "half-holing", and in the context of the thumb hole, "pinching".

The primary function of the thumbhole is to serve as an octaving vent. When it is leaked, the first mode of vibration of the air column becomes unstable: i.e., the register changes. In most recorders, this is required for the playing of every note higher than a ninth above the lowest note. The player must adjust the position of the thumb for these notes to sound stable and in tune.

The partial opening of the thumbhole may be achieved by sliding or rolling the thumb off the hole, or by bending the thumb at the first knuckle. To partially uncover a covered hole, the player may slide the finger off the hole, bend or roll the finger away from the hole, gently lift the finger from the hole, or a combination of these. To partially cover an open hole, the reverse is possible.

Generally speaking, the partial opening of covered fingerholes raises the pitch of the sounding note while the partial closure of open fingerholes lowers the pitch.