Q: What is a U-block playing?
When I started playing, automatically I used the curled tongue (U-block) to select single notes. For me it was a very natural thing to do. Later I learned to tongue block (TB) and pucker. Now I switch between those three embouchures. All have serious pro's and contra's. I guess the characteristics of puckering and TB-ing have previously been discussed.
For those who don't know how a U-block is done. You curl your tongue around the hole you want to play. In fact you block the holes right and left from the one you play. This could give you a good seal to play single notes.
Let me post you the pro's and con's of the U-block IMAO. Tonewise I'd place it in between pucker and TB. I'm convinced it gives you fatter tone than a pucker, but slightly thinner than a TB. It also allows you to play very fast and accurate. However for bending and other tongue-effects you have to leave the U-block and you loose an awful lot of speed. Also, for playing chromatic the U-block doesn't give me a satisfying tone. For the subtle Toots Thielemans tone, you need a pucker. For blues chromatic (George Smith) you need to TB. We have an expression "It's neither fish nor meat", which means it's neither here nor there. That's the feeling I have about the U-block for chromatic harmonica. For diatonic however I believe it can help you to fatten up your tone...you either have it or you don't. I think you really must be comfortable with the U-block in order to get any gain. To my students I always discourage the U-block in favor of a TB -- "Re: Tongue Blocking (N. Buffalo is a curled tonguer, nah-nah)" 19 May 95 SB
(FMI: "Re: Tongue Blocking ((U-Block)" 19-21 May 95 JT,TH, SB) (FMI: "RE: Tongue blocking (U-block): JT)