At one time I was in charge of arrangements for the Tokyo Clarinet Ensemble (est. 1979), mainly because there was no other writer who had enough time to compose for the ensemble. I wrote dozens of arrangements and three originals for this group. The members were patient and taught me the functions and characteristics of the instrument. The experience at that time became an irreplaceable and truly valuable asset when I started writing concert band music.
In the mid-1980s, Polydor Records Japan Co., Ltd. decided to produce a complete collection of band/chamber ensembles. The Tokyo Clarinet Ensemble was a part of the project. New sheet music is also required for recording, and one of several songs written for that purpose is this ""Eine Kleine Nachtmusik Movement 1"". In fact, I arranged all the movements of the work for clarinet sextet published by Ongaku no Tomosha, and I received an order for an arrangement that could be played more easily.
It's a well-known song, and you don't need any special knowledge to play it. The Eb clarinet can be replaced with Bb clarinet by manipulating a small part octave, but it is best to organize it according to the score in order to add brilliance to the overall sound.