When I learned to touch type, back in the mid-80’s, I was instructed to use a finger map that basically mirrors the left and right hand side. I’ve added a figure below and refer to it as the EDX finger map. In essence where you go down-right with your right hand (for instance from k to ,) you go down-left with your left hand (for instance from d to x). The middle finger has two letters on the the bottom row (left c and v, right m and n). We were allowed to choose a finger for b, which lies somewhere in the middle.
It feels quite natural, as you fingers follow the general direction that your arms arms are in, and there is no need to bend your wrists inwards.
What I find curious is that this finger map lay-out for the left hand seems to have all but disappeared, and I search for it from time to time out of curiosity, but all touch typing advice seems to reverse the left hand action, so you would go d to c with the same finger. For lack of a better description I refer to this the EDC finger map.
I’m curious again because when reading about dvorak, most people seem to agree that perhaps it is not faster, but at least their hands hurt less. But it seems to me that compared to the EDX finger map, the EDC finger map would indeed put more strain on the left wrist as it forces my left wrist inwards, whereas I can keep it comfortably in one line if I type as EDX.
So my question is: Does anybody know the ergonomic benefits of using EDX versus EDC that seems to have become the standard?