Air escaping through nose

Can anyone share an idea on how to prevent air escaping through my nose; particularly on holes 1,2 and 3.

Does this happen when inhaling, or exhaling? Or both?

On the blow (exhale). Particularly on the the Hole’s 1,2 and 3.

You may be using too much pressure. When playing harmonica, it’s generally helpful to relax your neck and shoulder muscles, and breathe gently but deeply from the diaphragm. Use the entire lung capacity, rather than shallow breathing from the upper part of the lungs. In order for the harp to sound good, the player needs to adopt a large jaw and throat opening, so that you can move a fairly large volume of air at relatively low pressure. Take the mouthpiece of the harp well inside your mouth. I have a couple of YT videos which may be helpful:

Steve, Thank you!! I didn’t quite realize the importance of Harmonica placement within the mouth. The tone is markedly deeper and the instrument more enjoyable to play. While it may take some time to relearn this technique I’m confident my playing will be more fun and easier on my wife’s ears. Richard

ps the videos are great.

Thank you, I’m glad the videos are a help and that you could immediately notice that how you enclose the harmonica in your mouth makes a big difference to how it sounds. Good luck with your playing!