Koi come in many different colors and patterns, the more common colors are white, black, red, yellow, blue, and cream.
While there are limitless possible variations of color and pattern, breeders have named a number of specific categories of Koi. The most popular category is called Gosanke, which is made up of the Kohaku, Taisho Sanshoku, and Showa Sanshoku varieties, all pictured below with many of the other major named varieties.
Thanks to the ingenuity and dedication of Japanese master koi breeders, the world is now blessed with a diverse collection of koi breeds and varieties. Present-day koi are so brilliantly colored that it's difficult to imagine all of them coming from the dull-colored fish grown for food in the mountains of Niigata, Japan centuries ago.
To novice koi hobbyists, the flurry of Japanese terms corresponding to these various breeds can be daunting. The advice commonly given is to get accustomed to the terms slowly and enjoy the learning process. The starting point of this learning process is more often than not with the three most established and most popular breeds of koi, namely, the 'Kohaku', the 'Sanke', and the 'Showa'. 'Gosanke' is the term used to refer to these three breeds taken together.