If it won't confuse you too much Vadim, don't you think it would have been easier if the people who named the notes on the fingering charts had put the concert pitch names alongside each one and let our sheet music be written in the same pitch as a piano? As things are we clarinet players are sometimes annoyed that we can't use piano music because it's always in the wrong key for us. It's not so bad when playing from the dots like this nut it's a nuisance when we play from chord symbols because again we can't work direct from the piano music. What do you think? Why are things like they are? How did it happen?

In order to have the same fingering on different size of clarinets,i guess.

Could be.