From 1778 on they were clarinet avid gamers only. Not long afterthat Mozart wrote his famous works for clarinet including the concerto for basset clarinet in A referred to as concertofor clarinet in A which are technically extraordinarily tough. Even with trendy contraptions they seem to be a problem forprofessional musisicians. At that point clarinets had five technically questionable keys. It is difficult to imagine that youcould play that music with those instruments at all, but it should have been possible, as the critics were excited andyou must not think that they didn't know what satisfactory in device making and playing was it was the time when stringinstruments like Stradivari violins were built. With every new musical and technical challenge craftsmen and avid gamers strived to stronger the hot and by far not perfect instrument. This advancement is akin to organic evolution of living species. Usually it was in small steps, shows forking, interdependencies of workshops and infrequently dead ends. Today a number of systems survived, on the only hand the German System a step by step benefit of Denner's System, it is played mainly in Germany and Austria. Then there are forks that technically and from the appearance remain German style: the Albert System or simple system that is utilized in Jazz and the oriental clarinet, both are similar to a German clarinet of around 1870. Shortly after this the German flute maker Theobald Boehm brought about two advancements to the device making world:On the only hand, he created a mathematical basis for the perfect calculation of the place of tone holes and on theother hand, he invented the hoop key.