It has been said that harmonica bending, the practice of bending notes is the most important technique that a harmonica player can learn. It has also been described as the most difficult technique to master! Therefore, it is usually not recommended for beginners until they have mastered the basics.
Note bending adjusts the pitch of a note by changing the direction of the airflow and the amount of force directed at the reed. It also requires using the tongue, throat and of course, the lungs. Due to the ability to manipulate sound by blending, it is an extremely popular technique for playing notes on a diatonic harmonica, giving that bluesy soul and feeling so desirable in playing blues and rock music. Blending can also be combined with other techniques to add versatility and style to your playing such as the train whistle effect.
The standard bend used on harmonicas, is the draw bend, which goes down in pitch. Different holes on the harmonica also have different capacities for bending. For instance, hole #1 on a C harmonica bends down a full note or one half tone or step, going from D to #C. Note that this is the same note that is played on the fourth hole but is now being done an octave lower. Hole #2, on the other hand, can bend down an entire 3 notes or one whole step, going from G to F.
The first six holes on the diatomic harmonica are also draw bends, meaning that the player inhales to change the pitch not exhaling or blowing into the harmonica, blows are down on holes 7 and up. For beginners, the draw blends tend to be easier to become skilled at. By mastering harmonica blending, you can get pretty close to playing all the notes that appear on the piano, both black and white keys.