The prefix "Narumi" is derived from the town of the same name in the Ichi Prefecture, where a locally made fabric can be found, whose weave pattern was said to resemble the pattern on the backs of these Koi. At this time, Asagi seemed to have appeared all over Japan, not just in Niigata and this is when interest in mutant fish led to their being kept back from the food crop and bred together for curiosity's sake, long before Koi were seen as a commercial proposition.
What to look for in Asagi
Ideally, the back of an Asagi should be evenly covered in scales that are pale blue at the spot where they enter the skin, but are a darker blue as they grow out. The sharper the definition between these two shades, the more impressive the Koi will look. Because the scales are so well defined in this variety, any missing or damaged scales will stand out, seriously devaluing an otherwise good Asagi. The head coloring is an important feature in Asagi that is rarely seen in perfect or near perfect condition. Ideally, it should be a uniform clear white but more often takes on an undesirable blue or grayish tint. In young examples, the bones of the skull show through, but this effect disappears as the translucent skin thickens. If there is a lot of head hi forming a hood pattern, the fish is known as a Menkaburi Asagi.
Asagi are fully scaled, nonmetallic fish with a long history, but because they closely resemble Magoi (the wild black carp). Some hobbyists see them as unrefined, dull, and not proper Koi at all. Certainly they are an acquired taste, far removed from the brilliantly tri colored modern Showa or the flashy Koi grouped in Hikariutsuri. But their quiet elegance serves as a counterpart to their more exotic pond mates and they also have the potential to grow very large.
Asagi have a long, yet simple history. The Asagi Magoi, one of the three recognized types of Magoi, is said to be the forerunner of all modern Koi breeds. About 160 years ago, two mutants Koi types arose from this proto-Koi, namely the Konjo and the Narumi Asagi. Although instrumental in the development of Matsuba Koi, the dark Konjo Asagi were not seen as having any value, and were kept mostly for food stock. However, Narumi Asagi have gone on to become one half of a recognized judging variety - the other being their Doitsu counterparts, or Shusui.
Asagi hi, more often than not, shows as a rusty red than the bright scarlet associated with the Kohaku and other Go Sanke varieties. Typically, it runs up from the belly to the lateral line or slightly beyond, in some cases also covering the jaw, cheeks, and some or all of the fins. On the pectorals it can be configured like the motoguro of Showa, or else spread out over the entire area of the fins. Wherever hi appears in this variety it should be symmetrical. Some Asagi have a greater than usual percentage of red patterning, which can extend almost up to the dorsal fin. These are known as Hi Asagi. Others - Taki Asagi - have a white line dividing the areas of red and blue on the flanks. Both these sub varieties are still grouped in Asagi.
The scalation on younger Koi will determine how it looks as the Koi matures. As the Koi grow, the skin stretches and the pinecone pattern will become more apparent. Those Koi with predominantly white scales with small dots of blue in the center will finish as a Koi with a deeply contrasted net pattern. Those with darker scales when small will produce a more even and deeper blue color, both of which are stunning. It should be noted that small Koi (10" or less) will have a darker line in the middle of the head. This should not be considered a defect as this will clear with age.