In the parlance of mechanical player-pianos, “hand-played” described a piano roll that was directly derived from a realtime human performance. After the initial punching of a roll, it could be retouched. Alternatively, a roll could be prepared entirely by a technician punching holes in a paper roll, measuring physical distances on paper to make the rhythm — no piano playing required. Conlon Nancarrow carried that practice to considerable extremes.
In today’s electronic music, especially in dance music, repeating patterns or loops made on a computer may be extremely regular and regularly repetitive, down to the level of milliseconds or frames. My once-upon-a-time student Francesco Tristano has described his preference in shows for playing some looped material live on the piano. It’s hand-played.Related