Showa Sanshoku, a member of the Gosanke family, are commonly referred to with the abbreviated name Showa. Showa have a black (sumi) body with areas of white (shiro) and red (hi) patterns overlaying the black.
Showa were first produced around 1927, when a Ki Utsuri was crossed with a Kohaku to create the first "old style" Showa. These original Showa had a dull yellow and brown pattern, and sometimes exhibited an unattractive grey-colored shiro.
In 1964, a breeder by the name of Kobayashi began crossing female Showa with male Kohaku. The resulting offspring showed drastically improved hi and shiro colors, and eventually produced the type of koi that we think of as Showa today. Most Showa seen in the koi industry today can be traced back to the Kobayashi bloodline.
Showa are koi with a black (sumi) base and areas of red (hi) and white (shiro) overlaying the sumi. The pattern created by the three colors should be distributed evenly about the body, with sharp, clean edges between areas of different color. Preferably, the hi should be the dominant color, with the sumi and shiro complimenting the hi in equal proportions.
If a Showa is more than 50 percent red when viewed from above, it is referred to as a Hi Showa. Hi Showa are sometimes difficult to differentiate from Hi Utsuri. The best way to tell them apart is to look for small areas of white, which would indicate that the koi is a Showa (Hi Utsuri have no white anywhere on the body).
Some Showa exhibit black patches at the base of the pectoral fins, known as "motoguro". Motoguro is a desirable trait among Showa, but clear or white fins are also acceptable. Solid black fins on a Showa are generally viewed as inferior.
When choosing young Showa, it is important to remember that the hi and sumi will darken and intensify as the koi grows older, and can fluctuate very much throughout a Showa's lifespan.