Kawai had been known for their pianos mostly I suppose before 1980. Marketing products at first under the Teisco name, they began making some analog synthesizers. Some can be found that have either Kawai or Teisco like 100-F and SX-210. See this Sound on Sound article on the SX400 for a lot of good history on this and a table showing a comparison/explanation of the early synths and their names near the end of the article. Their early products are fairly unique ones with a lot of analog chips and character. And their digital products set some landmarks in bang for buck. My K1m cost 300 dollars new in 1988 as I recall.
The SX's are DCO analog synths which are fairly nice for performance since all controls are a button push and a wheel turn away. And those include poramento and glissando, chord memory, etc. The SX-210 for instance can record two notes to do a 4 voice 2 osc/voice stack, or record all 8 notes for a thick monophonic sound. And resonance has 99 point resolution making it a little smoother than a lot of the digital control synths. THough it is one step to self resonance at the end of course :-).
The K3 'user waveform' built from Harmonics. It and the other analog filter machines use the SSM2044. K5, K1, K4 were all digital synths and I like the K1 and K5 a lot for really unorthodox sounds. The K1 particularly for AM sweep sounds. I really can't stand the sound of a piano from either anymore. The K5000 is the king of harmonic synthesizers and, according to Kawai's service head, their last synthesizer product for the forseeable future.
100-F 100P 60F 110-F SX-400 SX-210 SX-240 K3 K1/K1-II K5 K4 XD-5 K11 K5000