How the white keys map onto the black-key groups

Black keys come in repeating groups of 2 and 3. The white-key names hang off those groups in a fixed pattern — no counting from C, just look:

• C · white key just left of any 2-black group
• D · white key between the two black keys (in a 2-black group)
• E · white key just right of any 2-black group
• F · white key just left of any 3-black group
• G / A · the two white keys inside the 3-black group (lower / upper)
• B · white key just right of any 3-black group

Octave doesn’t matter — any C counts as “a C.” Same for the rest.

Why this is foundational

The next three lessons (two-black-key groups, three-black-key groups, middle C orientation) are all about getting fast at landing on a specific key without searching. Every later lesson — five-finger patterns, scales, chord shapes — assumes you can land on any C/F/G in under two seconds without looking it up.