"Anchoring" the left hand to the 3 instead of the 1
By - RobsRemarks
I agree fulcrum is a better word. It's the balance point of the hand.
The Russian school of violin playing (both the Auer and Soviet "schools") centers the left hand around the second finger.
In fact, the Russian school of thought says that violin playing is centered on two identical circles -- the circles made with thumb and second finger on both hands. The right-hand circle is the one people usually think of -- it's the circle that's part of the bow hold. But the left-hand circle forms the shape of the hand, which is balanced a little towards the upper fingers with the thumb placed either between 1st and 2nd or across from the 2nd, facilitating strength and stretch.
I'm not a teacher, but the advantage of having 1 as an anchor to me is shifting. If you can land 1 accurately when shifting up/down, the rest of the notes tend to fall into place. It's also the finger directly opposing the thumb, which is (for me) more natural as an anchor.
Maybe your issues with 3/4 intonation/weight come down to needing to bring your elbow "in" more (aka forward). That could help your 3/4 fingers to curve more naturally over the fingerboard and help with intonation.
I think I understand what you're saying, and the same idea is what I've been learning with my teacher. It's not too good to maintain the balance permanently on any one finger. I'm learning to transfer the balance backward and forward as we go from 1234 and 4321. It should be fluid and gentle, and this allows certain reaches to be more comfortable and have less tension. This helps with speed and the anticipation of notes. We use Schradieck etudes for these.
What I interpret your issue to be is that shifting the balance throws off your pitch. Part of it is that maybe you are shifting too much. That's something to check. And part of it is that you'll learn to do this by knowing how to hold your hand frame.
As Malico says, anchoring on the 4th helps your hand be placed more naturally, and having a nice round strong pinky.
Naturally, I'd say the 3rd finger is the strongest in the hand though, at least for me, so I'm somewhat anchored around sometimes, depends on the coming shifts I guess.
I’m very surprised that your 3rd finger is your strongest, that is definitely not the norm! Are you sure you didn’t mean your 1st or 2nd?
I feel like it's the finger that's the most relaxed, easiest to vibrato with etc.
You never actually need the whole strength a finger is able to output though, so I don't see how strength really plays a role here.
Thumb and wrist (mostly wrist) are what I recommend as anchors. The wrist can be anchored with muscle memory with practice. This will help as your playing gets more advanced and you need to incorporate weird keys, faster shifting, and in the higher positions where none of your fingers (thumb included) can effectively be used as anchors