The design was gradually modified and the number of tones increased up to 142, some models 152, with 5 button rows in left hand and 6 rows in the right. If you consider the price comparable with that of a piano, it was of great commercial importance. A few samples left the factory after the war, but for quality reasons a less demand the factory finished in December 1956. In Germany itself, as I mentioned, there was no great development of the playing techniques, and even in Argentina professionals began to develop first methods in the twenties, but mainly based on piano methods. No European conservatory included this instrument in its teaching program giving the instrument a low social position.
Many people believe it is something for poor street musicians.
But the fact that, like the violin, it lasts many years to achieve a certain level and the price show the contrary. Today things changed in Europe, and first Paris, later Rotterdam and recently many other French conservatories are offering lessons for bandoneon. The tonal range is the same as for the cembalo, and baroque music sounds specially pleasant. The maximum development was reached by Alejandro Barletta in Buenos Aires. Marino Rivero in Uruguay, a pupil of Barletta, made very many transcriptions of Bach, Frescobaldi and other composers of the baroque and he is perhaps actually the most advantaged player for classical and contemporary music on this instrument.