1

The key is depressed, immediately lifting the wippen and the jack. The latter pushes on the knuckle and the hammer starts moving upwards.

2

When the hammer is halfway to the string, the extremity of the key lever starts pushing the damper upwards, releasing the string.

3

Slightly before the hammer hits the strings, the jack reaches its motion limit when its toe is constrained by the letoff button.

4

The hammer continues moving upwards only by inertia, until it hits the string and rebounds back.

5

During the rebound motion, the hammer goes downward, but the knuckle lands on the repetition lever instead of the jack, kept down by the letoff button.

6

The hammer’s downward inertia pushes the repetition lever down, and the hammer tail is caught and held in place by the backcheck.

7

If the key is still depressed, the string is free to resonate.

8a

If the key is slightly (not fully) released, the backcheck releases the hammer tail and the repetition lever moves the jack back under the knuckle,

9a

A new full cycle is enabled without the key being fully released. This part of the mechanism allows fast-repeated notes to be played.

8b

If the key is fully released, the hammer falls back into its rest place, the jack returns to its rest position under the knuckle, and the string is damped.