Japanese 12-key flick keyboard layout, modelled after Android's flick keyboard.
Rather than being modal, it has the ability to apply modifiers to the previous character. In addition, users can tap a kana key to cycle through the various kana in that kana row (and associated small kana).
Note that because we cannot have tri-state buttons (and we want to be able to input katakana) we emulate a quad-state button using the symbol and shift layers. Users just have to tap whatever mode they want and they should be able to get there easily.