The garmon (гармонь) is a kind of Russian button accordion, a free-reed wind instrument. A garmon has two rows of buttons on the right side, which play the notes of a diatonic scale, and at least two rows of buttons on the left side, which play the primary chords in the key of the instrument as well as its relative harmonic minor key. Many instruments have additional right-hand buttons with useful accidental notes, additional left-hand chords for playing in related keys, and a row of free-bass buttons, to facilitate playing of bass melodies.
The garmons can be of two major classes: unisonoric, meaning that each button plays the same note or chord when the bellows is being expanded as it does when compressed, and bisonoric, in which the note depends on the direction of the bellowswork. Examples of unisoniric type are livenka (ливенка, after Livny, Oryol Oblast) and Khromka (Хромка, for "chromatic"). Bisonoric garmons are, e.g., Tula accordion (Тульская гармонь, after Tula) and talyanka (тальянка, "Italian")
The garmon is also known by the names garmoshka (гармошка) and garmonika (гармоника) .
The garmon is an important musical instrument for Azeri and Hamshen folk and popular music.
The treble keyboard is arranged so that a scale may be played by alternating between the two rows. The low and high octaves have identical fingering, while the middle octave differs. The three accidental notes are arranged so as to mirror the position of the left-hand chords that contain them.
The bass keyboard is arranged so that the principal chords for the major key are in the outer row, placed in circle of fifths order; the principal chords for the harmonic minor key are in the middle row; free bass notes are in the inner row. One free bass accidental note is included.
Some Garmons (often seen in Azeri music,) have a small right-hand piano keyboard and a unique bass keyboard of buttons laid out similar to piano keys. One row of buttons plays the "white" notes, while another row of "black" buttons has spaces mirroring the pattern of sharps and flats on the right-hand piano keys. The Nardin Gallery, has pictures and videos of these.