Initially sold for ¥39,000
Main keyboard to be used with the YIS ecosystem. It attaches to the central PU1 via a (very fragile-looking) ribbon cable. There's a volume control on the back, with a piezoelectric speaker hidden under the top left corner of the keyboard. It's entirely made of plastic, with woodgrain sides to match the wooden cabinet of the CRT display.
A KB2 model was also available, with chiclet style switches.