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General information about the diatonic accordion
The first diatonic accordions were made in the early 1800s. They had a row of 10 buttons on the side of the right hand.

For each note on the button board there are at least two reeds (and there can be up to 10) with different pitches for the bellows to move in and out. The bass notes and the corresponding chords are the root of the bellows in-motion scale and the fifth of the out-motion scale.

Diatonic accordions are widely used by folk and dance groups for their great tonal performance, simplicity, light weight, and low cost. This makes them one of the most popular accordions in the world. The keyboard note scheme is usually the same as that of a harmonica.

Single row diatonic accordions
The single-row diatonic accordion, melodeon or as it is sometimes called: "German style accordion" has a ten-button row as its keyboard. Since it is diatonic, these 10 buttons can produce 20 notes; 10 in the inward movement of the bellows and 10 in the outward movement. It has two diatonic bass buttons that make two bass notes and two chords. The bass notes and corresponding chords are the root (first note) of the scale for the in-motion and the fifth of the scale for the out-motion.


The organetto is from Italy and has up to 24 upper voice buttons and 12 bass buttons. The most popular type has two bass heads and a row of 10 upper part buttons. A second row with three or four buttons allows different fingerings. It has up to three reeds per note; the two in the middle movement are tuned with a tremolo, the third is an octave lower.

The two-row diatonic accordion
The origin of the two-row diatonic accordion is not exactly known as many versions appeared simultaneously around the world. To increase the range and compatibility with other instruments, another row of buttons has been added to the keyboard. The second row is also diatonic and can either be a semitone above the first row (e.g. scales B and C) or a whole fourth above the first row (e.g. G and C). These can be keys other than those given in the example. In the case of the semitone diatonic accordion, any note in the chromatic scale can be played.

Italian diatonic accordions

The Italian diatonic accordion has two rows, the second row is a full fourth above the first row. An additional partial row usually consists of five or six buttons of raised / lowered notes (major or minor). One note in the second row is the same tone. The same tone button plays the same tone regardless of the direction of movement of the bellows. This note is always the fifth (middle octave only) of the corresponding diatonic scale.

Three-row diatonic accordion
Three-row diatonic accordions are similar to two-row accordions and have a third row either a semitone higher than the original (now middle) row or a fourth above the second row. There are accordions with up to 12 bass notes. The bass notes and corresponding chords form the root note for the bellows in movement and the fifth of the scale for the out movement. There are also four and five row diatonic accordions. These follow the same principle as the three-rowed one.

Helikon accordion
The Helicon accordion is named after the Helicon tuba, which evolved from ram horn trumpets that were first used thousands of years ago. It is the Helikon bass reeds that give the bass notes their special tuba sound. The reason for this is that the bass reeds are much longer and wider than normal bass reeds. They produce deep tones that are very similar to those of the tuba. Very often the deep helicon reeds are fitted into a duralumin plate. These reeds can be up to 2.5 cm longer than the standard bass reeds. They were first used in Styrian diatonic accordions and can now be found in new piano accordions.

The Shand accordion

The Shand accordion was developed by the Scottish accordionist Jimmy Shand. It uses a diatonic semitone principle in the three-row keyboard for the right hand and a 96 bass standard system for the left hand. The rows of the right hand change notes with different bellows directions; the bass notes of the left hand do not change.

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