100-150 year old Rosewood can so dry that sections of piano can split along the grain very easily making it very difficult to work with. This Fallboard lid had to be reglued back together perfectly, sanded, filled and refinished with shellac in order that the repair be absolutely hidden.
Invisible casework repairs like this require many years working with wood and refinishing.
This was a John Broadwood piano and they were the inventors of the modern piano, supplying Beethoven with examples of their workmanship.