In 1998, I came to live in Zaandijk, The Netherlands.
'Bach in Bullekerk' was regularly in the local newspaper. Every month, at the Bullekerk, there's a Bach's Cantata played. In 2000, I started going there occasionally and in 2002, they stopped the monthly Bach's Cantata concerts after doing it for 25 years!!
There were some moments I still hear in my head, e.g. an exquisite duet between a clarinet and a soprano, and I still have no idea which Aria it was. The clarinet and the soprano were singing and intermingled with each other intimately, playfully. Such fine musical lines were moving in the air of the church, the Bullekerk, while the sun was shinning too. I was deeply moving.
The acoustic of the church played an important role to enhance the intensity of the duet, for sure; but no other material could ever replace the Aria. It was a very specific style, people say they hear it immediately when they unknowingly listen to Bach's music. Sophisticated, deeply emotional, and yet, "simple". Just two musical lines, two people, listening and talking to each other.
Was it the beginning of my fascination to Bach?
Is it why I'm so fond of, especially, Bach's two-voices work for piano?
At the same time, I also started playing the piano again and to my surprise, some pieces by Bach from my childhood were still in me after quite a long time not playing them!
Not only Bach, but also Scarlatti and other Baroque composers, have a special place in my life in general; and specifically in my musical life, in my piano playing life.
How do their music help our musicality growing?
The dancing forms demand our lively sense of rhytm, the polifony is a beautiful practice for both hands to be independent, the plenty of running sixteenth notes demand us to develop our sense of phrasing.
Others would mention 'technique' too, yet technique is not specific.
Technique is actually everything about how we do music. How to listen, how to study, how to practice; how to use our body, arms and fingers to make music; how to read the musical blueprints/music sheets; how to play for ourselves/ for others; etc.
If this is all technique, yes, the music of Bach and his contemporaries is good for our 'technique'.