Ginrin translates to “silver scale,” though these days the term covers far more than silver, it describes any koi with scales that carry an extra, crystalline shine, catching light in a way that looks almost like the fish is dusted with glitter. Like Doitsu, Ginrin isn't a standalone variety, it's a scale trait that can be layered onto almost any pattern. A Ginrin Kohaku or Ginrin Showa keeps its base pattern but gains a texture that regular-scaled koi don't have.
The trait is credited to breeder Eizaburo Hoshino, said to have first fixed the sparkling scale type in the late 1920s in Konan village, Niigata, a region already deeply involved in early Nishikigoi development. The extra shine comes from thicker deposits of guanine, the same reflective compound responsible for shimmer in many fish species, concentrated unevenly across individual scales rather than spread in the flat, even layer seen on standard koi.
Not all Ginrin scales look the same, and serious keepers distinguish between several types: Beta Ginrin has a diamond-shaped sparkle across the whole scale, Kado Ginrin sparkles only along the scale's edge, and Pearl Ginrin has a softer, rounder shine with less contrast. A koi covered edge-to-edge in strong, consistent sparkle across every scale is significantly rarer, and significantly more valuable, than one with just a scattering of shiny scales.
Because Ginrin is a scale quality rather than a color pattern, judges evaluate it as an added layer of quality on top of whatever base variety the fish belongs to. A Ginrin koi with a mediocre pattern doesn't score especially well just for having sparkle, but a well-patterned koi with strong, even Ginrin scaling is considered a genuine step up from the same fish without it, and priced accordingly.