| 1/00 | General design |
| 1/02 | General design of upright pianofortes |
| 1/04 | General design of grand pianofortes |
| 1/06 | General design of harpsichords, spinets or similar stringed instruments |
| 3/00 | Details or accessories |
| 3/02 | Details or accessories Cases |
| 3/04 | Details or accessories Frames; Bridges; Bars |
| 3/06 | Details or accessories Resonating means, e.g. resonant strings, soundboards; Fastenings of the resonating means |
| 3/08 | Details or accessories Arrangements of strings |
| 3/10 | Details or accessories Tuning pins or straining devices |
| 3/12 | Details or accessories Keyboards; Keys |
| 3/14 | Details or accessories Keyboards; Keys for actuation by the feet |
| 3/16 | Details or accessories Actions |
| 3/18 | Details or accessories Actions Hammers |
| 3/20 | Details or accessories Actions involving the use of hydraulic, pneumatic, or electromagnetic means |
| 3/22 | Details or accessories Actions for grand pianofortes |
| 3/24 | Details or accessories Actions for reciprocating of tremolo |
| 3/26 | Details or accessories Pedals or pedal mechanisms for half-blow or similar sound-modifying |
| 3/28 | Details or accessories Transposing devices |
| 3/30 | Details or accessories Couplers, e.g. for playing octaves |