Thumb Shift Keyboard (1980)
With the "Thumb Shift Keyboard," which came with the OASYS 100, the 50 letters of the "kana" syllabary were arranged on 30 keys in 3 rows, like an English-language typewriter. Once the operator memorized the keyboard's layout, they could quickly touch type characters. Keys were arranged to minimize the amount of finger movement needed to type commonly used characters and to allow for alternate use of left and right thumbs. A single character could be input with a single keystroke, which greatly improved on other methods which requires 2-3 keystrokes.