The mistake that isn't a mistake: same-finger digraphs
Some letter pairs are slow because of anatomy, not carelessness. Knowing which is which changes what you should practise.
Open your weak-pair list and you will probably find a few combinations that look arbitrary. Why should "de" be slower than "da"? Why does "ol" cost you time when neither letter is difficult alone?
Because in both cases one finger has to do two jobs in a row.
One finger, two keys, no overlap#
Fluent typing overlaps. While your right index finger is finishing J, your left middle finger is already travelling toward E. The motions stack, which is why a fast typist is not simply moving each finger faster — they are moving several at once.
A same-finger digraph breaks that. D and E both belong to the left middle finger. The finger must press D, lift clear, travel a row, and press E, and none of that can overlap with itself. The pair costs you the full serial time of two presses plus the journey between them.
- de, ed — left middle finger, home to upper row
- ol, lo — right ring finger, same reach on the other hand
- ju, uj — right index, and the reason "just" is slower than it looks
- ce, ec — left middle again, this time crossing three rows
Why the coach separates the two causes#
Typepace's analysis will not tell you that a same-finger pair is an accuracy problem when it is a geometry problem. The diagnosis layer checks the finger map before it writes a sentence: if both letters belong to one finger, the pair is reported as a same-finger reach, and the suggested fix is a rhythm drill rather than a slow-down drill.
This matters because the two problems want opposite treatments. An adjacent-key confusion — hitting R when you meant T — gets better when you slow down and let the correct motion settle. A same-finger reach does not get better when you slow down. It gets better when you stop trying to overlap a motion that cannot overlap, and instead learn the small deliberate pause the pair actually requires.
The blueprint's own example, corrected#
Our strategy document uses "R to T" as an example of right-index hesitation. It is not: R and T are both left-index keys on a QWERTY board, which makes the pair a same-finger reach on the left hand. The code diagnoses it correctly and the document is the thing that needs amending. We are leaving the error documented rather than quietly fixing it, because the general lesson — check the finger map before you write the sentence — is the whole point of this post.