Shusui

The Shusui represents a revolutionary moment in the history of koi breeding, marking the first successful cross between the traditional Japanese Asagi and the German Mirror Carp (Doitsugoi). Created in Tokyo by Kichigoro Akiyama (English sources often give Yoshigoro) in the early 20th century, the Shusui is essentially the Doitsu (German-mirror) version of the Asagi — replacing the Asagi's full net of scales with rows of enlarged blue-grey scales along the back — but this description hardly does justice to its unique visual impact. Instead of the full coat of reticulated scales, the Shusui features a smooth, skin-like texture with rows of large, dark blue scales along the center of the back, ideally two and up to four. This 'zipper' of scales is the hallmark of the variety and must be perfectly aligned and symmetrical for the fish to be considered high quality. The body of the Shusui is typically a pale, powdery blue, which provides a striking canvas for the bright red 'Hi' markings that wrap around the belly and sides. Because the fish lacks most scales, the colors appear more saturated and vivid than on their Asagi counterparts. According to the All Japan Nishikigoi Promotion Association, the name 'Shusui' takes one character from its creator's name and refers to the fish's blue body color. The challenge in breeding Shusui lies in maintaining the clarity of the blue skin; any dark spots or 'shimi' can easily ruin the clean aesthetic. Additionally, the red pattern should ideally be balanced on both sides of the body, often creeping up toward the dorsal scales but never quite touching them. The Shusui's sleek, aerodynamic look makes it a favorite for modern hobbyists who appreciate bold, clean lines and dramatic contrast. It is a testament to the ingenuity of early breeders who saw the potential in combining European genetics with Japanese artistry to create a koi that looks like a living, swimming painting.