'T ht02a' computer keyboard layout

31 December 2017
Canonical namet-ht02a.en.ergodox
Form factorSplit : Ergodox / Kinesis
InventorIan Douglas
Keys horizontally staggeredNo
Letters on thumb2
Uses AltGr for standard charactersNo
Moves non-character keys (ANSI/ISO)No
Changes 'shift' pairsYes
Changes top row (ANSI/ISO)No
Uppercase on different keyNo

Click image for larger view


Download the Keyboard Layout Analyzer .json file.


MetricRankRelative %
KLA original English prose7880.51
KLA original Programming12463.63
Den 1 English prose2088.94
Den 1 Programming8077.20
Homekeys words182.71
Homeblock words1527.94
Angle mod Homeblock words1337.94
Easyblock words1274.18
One-handed words10029.21
Homekeys bigrams3486.55
Homekeys trigrams3475.35
Homekeys quadgrams1361.02
Homekeys common words2281.30
Samefinger bigrams137 5.20
Overall ranking3254.93

Finger based metrics

Finger based metrics, as determined with Keyboard Layout Analyzer, using Patrick's original scoring model, and Den's first revised version.

We show the ranking Overall, for the broad Form Factor, and against other similar layouts (Peers), for English prose, assorted Programming, and Average of the two.

'Peers' means compared to other layouts with same characterics, e.g. ANSI/ISO vs Ergo, and matching 'Has letters on thumb', 'Uses AltGr for standard characters', 'Moves non-character keys (ANSI/ISO)', 'Changes shift pairs', 'Changes top row (ANSI/ISO)', and 'Uppercase on different key', as listed above.

 OverallOverallOverall ErgoErgoErgo PeersPeersPeers
Scoring modelEnglish proseProgrammingCombined English proseProgrammingCombined English proseProgrammingCombined
KLA original78 / 360124 / 36096 / 36064 / 10895 / 10876 / 1082 / 64 / 62 / 6
Den 120 / 36080 / 36038 / 36020 / 10870 / 10836 / 1081 / 61 / 61 / 6

English Word-based analysis

Home Keys Analysis

The Home Keys for this layout are shown with red dots in the image above, giving the following letters:


Home key bigrams, trigrams, quadgrams and common words

Scores are based on which fingers are used for the top 20 bigrams, trigrams and quadgrams, and top 30 common words, with the scores weighted by strength of finger used, and frequency of occurance of the text.

MetricRankWeighted scoreComponents handled and not handled
Bigrams3478.04 / 90.17th he in er an re on en at ha to or it is hi es nd ou ed ng
Trigrams3429.9 / 39.68the her hat his tha ere ent ion ter ith thi tio and ing for was you ver all wit
Quadgrams139.69 / 15.88that ther tion here this thin atio with ould ight have hich whic they ever from ough were hing ment
Common words2268.66 / 84.45the to a in is that on he it as at his are this an has not or of and for was with by be from I but have they
Home Key lettersEnglish words typeableLongest wordExample

Word count
Word length

Easyblock Analysis

The typical Easyblock Keys for this layout form factor are shown here:
Easyblock lettersEnglish words typeableLongest wordExample

Word count
Word length

Homeblock Analysis

The typical Homeblock Keys for this layout form factor are shown here:
Homeblock lettersEnglish words typeableLongest wordExample

Word count
Word length

Angle Mod Homeblock Analysis

The typical Angle Mod Homeblock Keys for this layout form factor are shown here:
Angle mod Homeblock lettersEnglish words typeableLongest wordExample

Word count
Word length

One-handed words Analysis

This looks at how many words can be typed with only left or right hand. We want these numbers to be low.
This metric was done "strictly" ... shifted or AltGr letters were only included if Shift or AltGr was on the same hand.
Note: we exclude the Dvorak one-handed layouts comparison, since clearly by design they can type every possible word with one hand.
Left hand lettersLeft wordsLongest left wordLeft exampleRight hand lettersRight wordsLongest right wordRight exampleTotal
jJuUgGiIaAeEoOdDqQyY44911Ouagadougou vflpzcshnrkwmbxt927tsktsks 541

Left handRight hand
Word count
Word lengthWord length

SameFinger Bigrams

This is a weighted analysis of same-finger usage.

The probability that a letter will follow another given letter is used to evaluate layouts by which letters pairs are on the same fingers. We multiply this figure by the percentage frequency of the first letter, in English.
We add the probabilities in both directions, for example "er" and "re".

There are some exceptions: We only look at lower case, and if the second letter is on the same key as the first, we ignore that pair.

The idea is to see how much a finger has to fly around, and if the two letters are on the same key (as in the split-case layouts) then it doesn't have to fly between them.

The metric does not measure how far the finger has to fly, just that it has to. I'll look at adding distance, row jumps, inward rolls, outward rolls, to this metric if possible.

Left pinky'jiq' 1.1251
Left ring'a' 0
Left middle'ue' 10.4706
Left index'gody' 90.3207
Left thumb'⍽' 0
Right thumb't' 0
Right index'vfcskw' 46.6013
Right middle'lhm' 4.2682
Right ring'pnb' 1.055
Right pinky'zrx' 0.0935
Both thumbs'' 0
Total 153.93

Word metric comparisons

MetricLowestLowest scoret-ht02a.en.ergodox scoreHighestHighest score
Home keysabcdef.en.ansi34723
Angle mod Homeblockalphametric.en.ansi135421692
Left hand wordsqgmlwy.en.ergolinear34449
Right hand wordsessie-3.en.ergolinear2692
Total single handedessie-3.en.ergolinear158541
Average single handedessie-3.en.ergolinear79270.5
Same finger bigramsseelpy-1.en.ergolinear8.01153.93

Fraser Street analysis

"Fraser Street" (thanks Shai) is a specially-crafted text in which most of the words are typed with only the left hand, on the QWERTY layout.
It was designed to highlight how much better the Dvorak layout is at hand alternation.
We ignore spaces and punctuation.

Left lettersRight lettersNeeds both hands

Fraser Street was in West Everett. Westward of Fraser Street was the great vast sea. Awed, we gazed seawards, attracted by crested waves which raced and ebbed. Children were scattered on the beach edged and strewed with seaweed. They waded in water as the sea surged in and retreated. They bagged crabs as eagerly as beavers saw trees. Brave crews, seafarers in fact, steered sea craft far away. The site of Fraser Street was not overrated.

Few vegetated in Fraser Street. Nobody wasted time abed. "Acts test the breed," was ever the sacred adage. Varied crafts and trades were represented. There was a caterer, a barber, a weaver, a cabaret, and a garage. Attracted, we started to see several scenes. We were greeted as friends.

The barber catered to a varied trade, representing diverse careers and different creeds. Saturday drew the best crowd. All were seated, relaxed, aware of fewer cares, less fagged. There we saw a few starved tattered beggars who bragged of "bracers" served at cafes after a wee meal of beef stew and cabbage. A better fare was reserved for those reared on earth's greater awards.

Fraser Street summary

Left letters typed429
Right letters typed429
Needs both hands23
Total letters typed881
Hand balance48.69 : 2.61 : 48.69

Typing lessons

Download some English words suitable for learning the layout.
Note if any files are empty it's because there are not enough words to create a lesson. This is most noticeable in the bad layouts.

Week 1Homekey words Day 1 Day 2 Day 3 Day 4 Day 5
Week 2Easyblock words Day 1 Day 2 Day 3 Day 4 Day 5
Week 3Homeblock words Day 1 Day 2 Day 3 Day 4 Day 5
Week 4Common / tricky words Day 1 Day 2 Day 3 Day 4 Day 5
Week 5Pangrams Day 1 Day 2 Day 3 Day 4 Day 5
Week 6So you think you can type? Day 1 Day 2 Day 3 Day 4 Day 5
Week 7Extra practice 1: Common words in text Day 1 Day 2 Day 3 Day 4 Day 5
Week 8Extra practice 2: Lorem ipsum and friends Day 1 Day 2 Day 3 Day 4 Day 5
Week 9Extra practice 3: Underused words Day 1 Day 2 Day 3 Day 4 Day 5