Your opinions about KOETSU URUSHI BLUE or VERMILLION

So, as I suggested, one of the Urushi models, the Vermillion apparently, has a different coil from the others.  Thanks to whoever brought that fact out.  As to Mijo's blanket statement that the paint has "absolutely no influence" on the sound, that is conceivable but so far only one man's opinion, although stated as a fact.  However, you can find persons who say otherwise.  I would say that Urushi's do sound quite different from Rosewoods, based on 20 years of internet testimony from many different sources; the Urushi is said to have a wider subjective frequency response, better bass and more extended highs, compared to the base Rosewood, and there are other physical differences between the two types, besides lacquer vs no lacquer (or clear lacquer which might be the outer finish on the Rosewood).  Rosewood Signature or Platinum might be another kettle of fish.

As I recall, all the color-coded variants of the Urushi vary from one another mostly by the lacquer finish.  However, there is one, and it might be the Blue or the Red (Vermilion), that uses a different coil wire (e.g., silver coated copper vs copper) and therefore would stand a chance of sounding different from the rest of the Urushi models.  This info is available on the Koetsu website, such as it is or used to be.  Happy owner of a Wajima variant here.