You gotta hear this...and look at that guy's intensity. 

Vitaly Dmitriev - Bach - Fuga in d-moll BWV 565

http://www.youtube.com/watch?v=UBmajjf5WKE

Fabulous!  His left and right hands have minds of their own!
Swatne.

A couple months ago a french band called Les Yeux Noirs (the black eyes) played a small concert here in Minneapolis.  The accordion player (he was incredible too!) had the same type of button accordion and I asked him about it afterwards.  it's chromatic, but has an interesting setup for the keys.   You can find it here:  http://www.thecipher.com/CBA_5row_Grids.pdf  

If you get the chance to hear this band, you should.  They are wonderful!  Two violin playing brothers with guitar, bass, drums, accordion.  They play a lot of fast gypsy music.

Swatne.

This is a Russian chromatic button accordion (CBA). It is fully chromatic and the same note sounds on both push and pull.

Russian button accordionists use the B-system (as opposed to the C suystem that is used in France) are well known for their accomplished playing of classical music. Others include Friedrich Lips and Lidia Kaminskaya.

Russian players call the accordion "bayan". Search Youtube on "bayan accordion" (bayan is also an unrelated Filipino word) and you'll find dozens of clips of Russian players, playing mostly classical music and some Russian and gypsy folk music.

Chromatic accordions have anywhere beettween three and five reeds per note which can be invokes in various combinations:

main reed (clarinet) and either one or two tremolo reeds

lower octave reed (bassoon), and upper octave reed (piccolo).

For this piece the tremolo reeds have been omitted and an octave combination has been used.

The button keyboard predates the piano keyboard on accordions and is considered by many to be superior due to the wider range available in the same space, the duplicate note locations available, and the symmetrical note arrangement that allows the same fingering patterns and chord shapes to be played in any key simply by changing the location of the hand.

Those who play diminished tuned chromatic harmonica will have some familiarity with the layout of the CBA button board.

On a B-system instrument, the outside row is tuned B-D-F-Ab, repeating for each octave - a diminished 7th chord.

The next row in is tuned a semitone lower - Bb-Db-E-G.

The third row in is tuned A-C-Eb-Gb.

The fourth row duplicates the first and the fifth row duplicates the second. These helper rows make it possible to migrate patterns based on the outside tow inward without modification.

On C-system instrument the outer row is C-Eb-Gb-A and each succeding row goes down in pitch instead of up. That's the instrunment you hear on all that fancy Parisian waltz stuff. One of the greatest French C-system players nowadays is Richard galliano, whose work can also be sampled on Youtube.

Play straight down a row and you get minor thirds. Play diagonally inwards and downwards and you get ascending major seconds. Play diagonally outwards and downwards and you get semitones. And so on - it's all completely consistent.

On instruments used for classical music, the left hand may mirror the right, or it may have a pattern of bass notes and chords (or both, with a converter switch). Having bass notes only in the left hand is known as "free bass" or Bassetti bass as opposed to the Stradella bass setup of bass notes and chords.

I acquired a B-system Russian accordion with Stradella basses a few months ago and have been having a lot of fun with it (as time allows).

Winslow