Asagi are nonmetallic, fully scaled fish with a long history, but because they closely resemble Magoi (wild black carps). Hobbyists consider them unrefined, dull, and not proper Koi at all. In a way they're an acquired taste, far removed from the brilliantly colored Modern Showa or the flashy Koi clustered in Hikariutsuri. Their quiet elegance is a counterpart to their more exotic pond mates, but they can also grow very large.
Asagi have a long, but simple history. The Asagi Magoi, one of three types of Magoi, is thought to be the forerunner of all modern Koi breeds. There were two mutant Koi types that came out of this proto-Koi about 160 years ago, the Konjo and the Narumi Asagi. The dark Konjo Asagi were instrumental in the development of Matsuba Koi, but they weren't considered valuable and were kept mostly for food. Narumi Asagi have gone on to become one half of a recognized judging variety - the other half is their Doitsu counterparts, or Shusui.
"Narumi" is derived from the town of the same name in the Ichi Prefecture, where one can find a locally made fabric whose weave pattern resembles the pattern on the backs of these Koi. The Asagi fish seemed to have spread across Japan, not just in Niigata, at this time, and it was at this time that mutant fish were separated from the food crop and bred together for curiosity's sake, long before Koi were considered a commercial proposition.
Asagi: What to expect
The back of an Asagi should be evenly covered with scales that are pale blue where they enter the skin, but darker blue as they grow out. The sharper the differentiation between these two shades, the more impressive the Koi will look. Despite the well-defined scales of this variety, any missing or damaged scale will stand out, seriously devaluing an otherwise fine Asagi. The coloring of the head is an important feature of Asagi that is rarely seen in perfect or near-perfect condition. Ideally, it should be a uniform, clear white, but more often than not, it has an undesirable blue or grayish tint. When the skin is thin, bones of the skull can be seen through the translucent skin, but this effect disappears as the skin thickens. The fish is called a Menkaburi Asagi if it has a lot of head hi forming a hood pattern.
More often than not, Asagi hi resembles rusty red rather than the bright scarlet associated with the Kohaku and other varieties of Go Sanke.It typically runs from the belly up to the lateral line, or slightly beyond, in some cases also covering the jaw, cheeks, and all or some fins. Its configuration on the pectorals can resemble the motoguro of Showa or it can be spread over the entire area of the fins. The hi should be symmetrical wherever it appears in this variety. There are some Asagi that exhibit a higher than usual percentage of red patterning, which can extend almost as far as the dorsal fin. They are called Hi Asagi. Taki Asagi has a white line dividing the areas of red and blue on the flanks. These two sub varieties are still grouped as Asagi.
The young Asagi...
Scalation determines how a Koi looks as it matures. Koi's skin will stretch as they grow, making the pinecone pattern more apparent. White scales with small blue dots in the center will result in a Koi with a highly contrasted net pattern. The blue color of those with darker scales will be more even and deeper when they are small, both of which are beautiful. Small Koi (10" or less) have a darker line running through the middle of their heads. This is not a defect and will fade as the fish grow.