WieWaldi If this video is true, Chopin said the easiest key for beginners to learn is B Maj, as there are all 5 black keys involved and those are very easily to locate and ergonomically very well suited to the shape of the hand.
I was taught the same thing, and have learned additional information since.
(1) The natural position of the hand is sort of round with the thumb and little finger dangling below the longer middle fingers. Spreading the hand so that the fingertips touch a flat surface is an unnatural habit we acquire, and C major aggravates this. Additionally, in C major we can't bring the hands further into the keyboard so we get these curled fingers as in those old "hold a ball" instructions. The "mostly black key" major scales make for a more relaxed hand.
(2) The "mostly black key scales" (B major, Db major, Gb major) make for easy orientation through visual cues. Also, if playing them hands together, your thumbs play at the same time, and the cue for thumbs are, in fact, the white keys, which stand out.
I know several teachers who teach B, Db, and Gb major first.
There is also a principal in pedagogy that puts concrete experience before abstract, concrete before symbolic, so that the abstract and symbols attach themselves to the concrete and physical experience. Thus you play B major first. Then see it as notation.
Chords themselves can also be taught by colour. The major chords are:
(all white) C, F, G
(bl wh bl) Db, Eb, Ab
(wh bl wh) D, E, A
(mishmash) B (wh bl bl) and Bb (bl bl wh)
I have seen little kids master these in a couple of weeks - an adult might get there in a week - because you're orienting by pattern, which the piano keyboard layout facilitates.
Notice that I have managed to write this information without trashing an proposed alternative system.
