A novice harmonica player posted this message to the Harp-l list:
As a beginner, I pucker for everything, and find tongue blocking to be very difficult. Is it true that the great Chicago blues tone can only come from tongue blocking? I think I read that Little Walter and others tongue blocked most of the time. Is anyone getting “that” tone while puckering?

By the way, “tongue blocking” refers to a technique for getting a single note in which the mouth covers 3-4 holes, and the tongue covers (or “blocks”) all but one. “Puckering” means narrowing your lips to get a single note. So it’s all about how you get a single note.

Butterfield was a pucker player, and Charlie Musselwhite is a self-identified pucker player too. I think both these guys sound great. That’s not a direct answer to the question, but it’s a big hint as to what the real question is.

As a beginner, I think you’re better off working on getting a big sound with whatever embouchure comes most easily to you. If you stick with the harp, sooner or later you’ll learn additional embouchures. In the meantime, making notes sound loud and clear is more important than playing a particular embouchure.

Getting a big sound is more about breathing from the gut and relaxing your throat than it is about your embouchure. See the breathing exercises at this site for more info.