Enthium: Engrammer meets Hands Down Promethium

Suraj N. Kurapati


  q y u o / x l d w z
b c i e a , k h t n s v
  ' - = . ; j m g p f
            r

Legend: QWERTY=white; Engram=gold; Enthium=blue; Differences=green. Rendering of this layout on an ortholinear keyboard. Rendering of this layout on a row-staggered keyboard. Rendering of this layout on my Glove80 keyboard. Photograph of this layout on my Glove80 keyboard.

  1. Ignition
    1. Training
      1. Evaluation
        1. Refinement
          1. PF and WV
            1. Q and Z
              1. B and V
                1. O and U
                2. Performance
                  1. Conclusion

                    Ignition

                    Intrigued by the Hands Down Promethium keyboard layout, which enhances the Engram layout with a HJKL cluster for Vim as well as advanced layout design and optimization heuristics pioneered by Alan Reiser’s Hands Down family of layouts, I sought to improve upon its placement of punctuation, in the spirit of the Engrammer layout, by moving apostrophe to a different finger entirely from YOU and I so it can be typed without same-finger bigrams such as you'd, I'd, they'd.

                      f p d l x ; u o y b z
                      s n t h k , a e i c q
                    \ v w g m j / . = - '
                              r
                    

                    This change reduced same-finger bigrams from 0.58% to 0.55% in Cyanophage’s analyzer, motivating me to continue customizing the layout and nuances further. Notably, I mirrored the layout horizontally because I’d like to keep all vowels on the left hand (just like Dvorak and Engram/mer), but I was unable to move the R thumb key to the right hand in Cyanophage’s analyzer playground. Curiously, this resulted in a lower Total Word Effort than the canonical version — but why?

                      b y o u ; x l d p f
                    q c i e a , k h t n s z
                      ' - = . / j m g w v
                                r
                    

                    Training

                    Next, I began practicing this layout with a fresh training profile on KeyBr. After nearly 7.5 hours of training, I finally unlocked all the alphabets at an average speed of 42.6 WPM and an accuracy of 95.82%, using my Glove80 keyboard.

                    KeyBr status upon unlocking all letters. KeyBr progress upon unlocking all letters. KeyBr statistics upon unlocking all letters.

                    During the rigorous training, I wrote the following observations in my notebook:

                    Evaluation

                    I spent a day with the layout in the real world to evaluate its effectiveness in the terminal and Vim (especially on my Linux laptop keyboard), and noticed that:

                    Refinement

                    PF and WV

                    I really didn’t want to deviate from the canonical Hands Down Promethium layout (this “Enthium” derivative was just supposed to be a simple horizontal mirror, plus some rearranged punctuation marks) so I reluctantly went to the keyboard layout analyzer playgrounds to see how bad it would be to swap PF with WV and to my complete surprise, this change hardly affected the layout’s performance:

                      b y o u ; x l d w v
                    q c i e a , k h t n s z
                      ' - = . / j m g p f
                                r
                    

                    I’m so glad this experiment worked out because it makes the layout a lot more comfortable for me in practice and it would also further reduce the barrier to entry for others seeking to switch over to Enthium from the Engrammer layout. :)

                    Q and Z

                    After the first month of real-world use, I also swapped Q with Z to be like Engram (with Q typed by the right pinky finger) in order to avoid one-handed QU sequences (in favor of hand alternation) which overwork the left pinky finger during KeyBr training (see the last observation above) and in real usage.

                      b y o u ; x l d w v
                    z c i e a , k h t n s q
                      ' - = . / j m g p f
                                r
                    

                    This deviation incurred a modest increase in Oxey’s analyzer’s Total Redirects from 0.350% to 3.389%, along with a decrease in Onehands from 2.206% to 2.091%, and a significant increase in the Total Rolls score from 43.816% up to 44.055%. Similarly, Cyanophage’s Total Word Effort score decreased from 735.9 to 735.1, along with a negligible increase in the Effort score from 398.34 up to 398.38, and with similarly modest differences in the Trigram Stats score distribution. In contrast, there was no change at all in the KeySolve analyzer’s statistics!

                    B and V

                    After the second month of real-world use, I reverted the previous Q and Z swap and then rotated B and V out from the upper row to the home row lateral in order to avoid reaching up with short pinky fingers or those weakened by convention.

                      q y o u ; x l d w z
                    b c i e a , k h t n s v
                      ' - = . / j m g p f
                                r
                    

                    In the Cyanophage analyzer, this change reduces Pinky/Ring Scissors from 0.49% down to 0.35% (huge drop!) and Skip Bigrams (2u) from 0.30% down to 0.29%. The other analyzers don’t fully comprehend the placement of lateral pinky keys, as explained in the note at the top of each analyzer’s respective subheading, but Oxey’s analyzer reports a notable reduction in SFBs from 0.829% to 0.818%.

                    O and U

                    O and U are swapped (changing the inward-rolling YOU into a redirecting YUO) to distribute finger workload more evenly (especially for the middle finger) and to avoid same-finger bigrams on AU (as in “author”) and EO (as in “people”).

                      q y u o / x l d w z
                    b c i e a , k h t n s v
                      ' - = . ; j m g p f
                                r
                    

                    This change was suggested by the creator of Cyanophage’s Analyzer himself 🤩 since it reduced SFBs from 0.55% to 0.49% and LSBs from 0.23% to 0.20% in his analyzer. Similarly, it reduces SFBs to 0.795% in Oxey’s analyzer, elevating this layout to 🥇 first place in Pascal Getreuer’s performance rankings for SFBs and LSBs!

                    Performance

                    The keyboard layout community commonly recommends Pascal Getreuer’s guide and comparison table as a starting point for layout exploration, and you’ll see that Enthium is statistically among the best layouts there:

                    These results come from Cyanophage’s analyzer, as detailed in the README. Also, I’ve tabulated all statistics for Enthium and related layouts for completeness.

                    Conclusion

                    The differences between Engram/mer and Enthium are so minimal that one might switch to it completely with about 6 hours1 of practice, spread over 2-3 days (start Friday and use weekend), to unlock all letters in KeyBr training. Enjoy!


                    1. I’m giving a shorter estimate than my own elapsed time since I trained with Promethium before swapping PF with WV; see my observation on clearing W


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