The exact origin of Utsurimono is unclear. Some authorities claim that these koi are of Magoi lineage, first produced in 1925 by Kazuo Minemura. Others believe that they are of much more recent Showa descent. Both theories are hard to disprove; all koi originate from Magoi, and it's not difficult to view a Shiro Utsuri as a "defective" Showa without the hi, just as a Shiro Bekko is basically a Sanke lacking a third color. Nowadays, however, Shiro Utsuri parent koi are spawned together to produce this specific variety, and only a few arise unwanted from Showa spawnings.
Ki Utsuri is a very old variety traceable back to 1875, at the beginning of the Meiji Era. Eizaburo Hoshino, who was also responsible for improving Sanke bloodlines in the early twentieth century, coined the term "Ki Utsuri" for the koi. Before this, they were earlier known as Kuro-Ki-Han.
What to look for in Utsurimono...
Like a Kohaku, Shiro Utsuri are classically simple, two-colored koi. Therefore, great store is placed on the quality of the white skin. This should be the color of snow with a healthy, yet subtle sheen.
Shiro Utsuri are most often confused with Bekko, but by applying the same criteria that differentiate Showa from Sanke, the difference becomes clear. A Shiro Utsuri is a black fish with white markings, a Shiro Bekko is the reverse, and all Utsuri sumi is of the typical Showa "wraparound" type.
The sumi should ideally be jet black and glossy, as in Showa. To be sure of the quality of the sumi, on inspection in good daylight, a Shiro Utsuri should maintain this deep black, for some can appear to have very dark, chocolate-brown markings, which is a fault. Another fault is too much black on the fins. Rather than neat motoguro on the pectorals, low-grade Shiro Utsuri exhibit solid sumi at the ball joint, which radiates outward. If this sumi is excessive, the whole fin will appear black. Dorsal and caudal fins are allowed some sumi, but again, if there is too much, the koi will appear unbalanced. Ideally, the white on the finnage should set off the body sumi. Shiro Utsuri, like Showa, should ideally display the same classic motoguro on their pectoral fins, and a modern taste for white predominance has become popular in both varieties.
Head patterning of Shiro Utsuri can range from the classic lightening strike or V-shape shared with Showa, to relatively small counterpoints on the white skin. These don't have to be symmetrical, but the edges should be clearly defined. Too much black on the head, especially if there are several small patches rather than a continuous pattern, makes for an inferior koi.
The chemistry of the water in which these koi are kept can influence how they look. Sumi develops best in hard, alkaline water, but in softer, more acidic ponds it takes on a grayish tinge.
Hi Utsuri are best viewed as a Showa without the white. Until recent years, the hi was rarely scarlet, but out crossings with Kohaku have greatly improved upon this variety. Some breeders have also reintroduced Magoi genes into their strain of Hi Utsuri, which allows the koi to attain a greater size without any falloff in pattern or skin quality. the pectorals rarely show true motoguro: more often they are striped black and red, with a red leading edge.
The yellow of this variety more often than not, tends to be pale and washed out, and both Hi Utsuri and Ki Utsuri are prone to developing shimis. Curiously, Kin Ki Utsuri are quite common, while the nonmetallic equivalent has almost vanished from the hobby.
The skin of young examples often give few clues as to how the finished koi will look. The most common "fault" in yearling Shiro Utsuri is a yellowish head. This is interpreted in a number of ways. Some see it as a sign that the fish is male, or that it will grow into a quality koi, though some examples never quite lose this tinge. Similarly, the white on the body can appear rather dingy, as areas of sumi still to arise give the skin a bluish gray tinge. It is said that the best way to tell to how the finished koi will look is to examine the white at the base of the tail, which clears sooner than the rest of the body.
Also, as with Kohaku, when choosing young Shiro Utsuri, steer clear of fish that look like miniature versions of the ideal adult. More sumi will almost certainly come later, making the koi black heavy.