Performing solo is the most basic and authentic form for Hartwin to show his creative side. He played many solo concerts all over Europe and his music is perfectly suited for small and very intimate concerts and bals in people’s living rooms, small venues, or little churches. Hartwin also published a sheet music book called ‘Out of the box’ featuring one hundred of his original tunes.

His first solo albums, 'Dance Tunes' and 'Waterman' include only self-penned material excisting of fine melodies played in a delicate and touching way. The honest and calming tunes on these albums reflect the symbiosis of Hartwin and his melodeon.