BIAS BS-1 ( OEM is Coron DC-860 DS-7 ) Drum Synth, 80's Japan as used by Yellow Magic Orchestra

BIAS BS-1 ( OEM is Coron DC-860 DS-7 ) Drum Synth early 80's Japan in mint condition with instruction sheet ( copy, see last photo ) and box.
This is rare percussion synth by musical instruments shop Ishibashi Gakki early 80's originally developed for Yellow Magic Orchestra. Currently its revival came with the techno pop band Polysics, which uses the BS-1 in a very unique way. Listen to their song " Baby BIAS " which was made using a BS-1 ( not this one ).