This looks odd, could be fake. The original Onyx’ from the 80’s had longer bodies & flat bottom. Never seen a slant front bottom on an Onyx before - I have only only seen this shape on Koetsu Black Goldline & Std Koetsu Red/Rosewood. The Rosewood Signature has a flat bottom.
Try Melvin Ang at Koetsu South East Asia - he is very good on Koetsu support.
Try Melvin Ang at Koetsu South East Asia - he is very good on Koetsu support.