Cheaper version of the Yamaha CX5F with rubber dome switches (also known as chiclet keyboard). Given how bad the real mechanical keyboard is already, this one should be probably avoided at all costs.
The keyboard layout is also slightly different, probably some of the keys were inherited from the original KB2 keyboard of the YIS system. A keyboard overlay sheet (OV01) was available for the CX5 and YIS303 computers to help remember the position of shape characters. A 1983 pre-production shows what looks like a "DX green" STOP button which would have looked great next to a Yamaha DX100, and no venting holes on the top.
MSX BASIC v1.0
3.58 MHz Zilog Z80 CPU
32 kb (up to 64 kb) RAM, 16 kb VRAM, 32 kb ROM
General Instruments AY-3-8910
SFG-01: FM tone generator (4 operators, 8 algorithms)