[minikomi]

The Japanese alphabet is divided up into consonant vowel pairs like

     a i u e o
     ka ki ku ke ko
     ta chi tsu te to etc.

You can see a table on wikipedia: https://en.wikipedia.org/wiki/Hiragana

The input system plays on this in that each set has a button, which you press and then release or swipe in one of four directions - thus giving the 5 possible inputs for each one. The modifier key changes a few characters - eg a Ha は can become Ba ば or Pa ぱ ..

    [ a  ][ ka ][ sa ]
    [ ta ][ na ][ ha ]
    [ ma ][ ya ][ ra ]
    [mod ][ wa ][punc]

Then for a single letter you have:

      u
    i a e
      o 

So, If I want to input the word for tokyo I'd go:

    down on ta - と (to)
    up on a - う (u)
    left on ka - き (ki)
    down on ya - よ (yo)
    modifier key - convert よ to combining ょ - thus making きょ (kyo)
    up again on a - う (u) 

By this point 東京 should appear in the selectable kanji above the keyboard - if not I can press a little chevron to expand the selections.

[blinduck]

This was very informative. Thanks!