Richter-tuned harmonica

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages) This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Richter-tuned harmonica" – news · newspapers · books · scholar · JSTOR (March 2013) (Learn how and when to remove this message) This article may need to be rewritten to comply with Wikipedia's quality standards. You can help. The talk page may contain suggestions. (June 2014) This article possibly contains original research. Please improve it by verifying the claims made and adding inline citations. Statements consisting only of original research should be removed. (September 2017) (Learn how and when to remove this message) (Learn how and when to remove this message)

The Richter-tuned harmonica, or 10-hole harmonica (in Asia) or blues harp (in America), is the most widely known type of harmonica. It is a variety of diatonic harmonica, with ten holes which offer the player 19 notes (10 holes times a draw and a blow for each hole minus one repeated note) in a three-octave range.

The standard diatonic harmonica is designed to allow a player to play chords and melody in a single key. Because they are only designed to be played in a single key at a time, diatonic harmonicas are available in all keys. Harps labeled G through B start (on hole 1 blow) below middle C, while Harps labeled D♭ through F♯ start above middle C (C₄). Here is the layout for a standard diatonic harmonica, labeled C, starting on middle C (C₄).

Although there are three octaves between 1 and 10 "blow", there is only one full major scale available on the harmonica, between holes 4 and 7. The lower holes are designed around the tonic (C major) and dominant (G major) chords, allowing a player to play these chords underneath a melody by blocking or unblocking the lower holes with the tongue. The most important notes (the tonic triad C–E–G) are given the blow, and the secondary notes (B–D–F–A), the draw.