Reaching one more note
You already know a small version of this. Stage 1's low/high fingers (low-and-high-fingers)
taught you to nudge a finger a half step off its "default" spot, without moving your hand — a
2nd finger sliding forward to touch the 3rd, say. Stage 6 generalises that same move to a
whole step or more, on any finger, in any position.
Extension: reaching forward without shifting
An extension stretches a single finger past the interval it would normally cover in your current hand-frame, to reach one extra note — without moving the hand or the thumb.
How to play it
Keep the hand and thumb exactly where they are for the normal 4th-finger D. Only the finger itself reaches forward for E, then relaxes back.
A shift moves the whole hand's reference point; an extension reaches one note past it and springs back. For a single passing note, that's often faster, quieter, and less disruptive than shifting there and immediately shifting back.
Contraction: reaching backward without shifting
A contraction is the mirror image — pulling a finger back inward, toward the hand, to reach a note that would otherwise need a shift down.
The physical feel: release, don't stretch
The hand has to open, not tense up — the same "no squeeze" principle Stage 0's
the-left-hand-frame already taught for the static hand. A common image: think of the palm
opening the way a hand slowly opens around an orange, rather than a rigid, forced reach.
Imagine the target pitch first, then feel for it — the same audiate-then-place order Stage 8's
hearing-it-first already teaches, now aimed at a finger stretch instead of a whole phrase.
Pivoting: a named refinement (REFERENCE)
Galamian calls it a "retarded shift" or "half-shift"; Ruggiero Ricci called it "pivoting or crawling." Either name means the same thing: combining a small shift with an extension or contraction — the hand moves only part of the way toward a new position while one finger (often the 1st) stays anchored where it was, letting the hand "creep" up gradually instead of jumping the full interval in one shift. It's a genuine technique, useful for smoothing a fast passage that would otherwise need several separate small shifts in a row — but it's a refinement on shifting fluency, not something this stage asks you to drill. Know it exists; you'll meet it again if you ever tackle a passage that calls for it.
Try it
Try
On the G string, play the normal 4th-finger D, then stretch that same finger to E without moving your hand. Feel the palm open, not clench. Then in 3rd position, play the normal 1st-finger C, and pull it back to B the same way. Both times, check: did your thumb move? If it did, that was a shift, not an extension.
The usual mistake
Turning every extension into a small shift — moving the whole hand a little instead of just stretching the one finger. That defeats the purpose: an extension is supposed to be faster and quieter than a shift precisely because the hand's reference point doesn't move at all.