As with the titles used in the two books of organ pieces that preceded them, there is no mystery here about the reference to J.S. Bach. The Trio Sonatas must therefore be presented in groups of six! They each have three movements (fast - slow - fast), alternating minor and major modes.
Only the first one (written much earlier), does not place, as it should, its slow movement in the relative tone. Without going so far as to say that anyone who has not handled three equally important voices in a contrapuntal game has lived in vain... it is enough to have experienced this jubilation to be unable to do without it. The music written here had no other ambition.