A 9" Kohaku Next Day Koi ZNA Potomac Friendship Award winner

Looking at all of your prized Living Jewels, you are certain that you might have a Grand Champion koi amongst them. Not that you are biased, of course. But at some point you will probably ask yourself “how can I tell?” Here’s a little background and some things that you will need to consider when judging koi fish.

Koi Judging Background

Koi judging originated in Western Japan in the 1960s with the formulation of the Zen Nippon Airinkai (ZNA). The then-local hobbyists who held shows needed criteria with which to properly judge the koi and select winners.

When the judging structure was first devised, the ZNA realized that judging standards would need to be more fluid (take that pun where you will) to allow some flexibility in judging the ever-expanding variations and sub-classes of koi that were developing. It was determined that formal on-the-job training, would be the main means of transferring knowledge as opposed to writing rules and standards down.

It is quite a feat to become a certified judge requiring dedication and time. It is a thorough process that involves first being an enthusiast and owner, as well as apprenticeships and testing.

Judging Koi Fish in the U.S.

If your koi is going to be judged in the U.S., there are three bodies that judge koi shows.

  • Local certified affiliates of the Japanese ZNA (who adhere to the same rigorous Japanese judging standards)
  • The Associated Koi Clubs of America (AKCA)—started in 1983—whose judges go through a similarly intensive certification process to those in the ZNA
  • The American Koi Judges Association (AKJA) was formed as an offshoot of the AKCA, and whose judges are invited to judge shows around the world. In some instances judges are members of multiple associations.

Koi Judging Criteria

There are several main categories that koi will be judged on. In many instances, the particular show is responsible for setting the categories, rules and regulations to judge the koi in the competition.

As koi will change in size, color, shape and—in some instances—pattern over the course of their lives, the basic judging criteria is adjusted or weighted to account for the particular traits that are more prevalent during the koi’s particular stage of development.


This is ordinarily the most heavily weighted category. It deals with everything on the body being in the right proportions and without deformities, irregularities or infections. From the correct number of eyes, fins and barbels to the correct shape and symmetry, all are taken into account.

The koi should be fusiform (or torpedo shaped), being narrower at the mouth, widening around the shoulders and then tapering back towards the tail. The biggest part of the body should be in the shoulder region (between the back of the gill plates and beginning of the dorsal fin). If it widens after the pectoral fin, it is referred to as “pigeon breasted.” A powerful peduncle (the area from the anal fin to the beginning of the tail) is also a good trait.

The mouth can’t be too pointy, and a wide head with a slightly convex forehead is preferred. Fin pairs should all be in proportion to one another and all fins need to have strong and undamaged rays with no sign of previous fin rot. Interestingly, it is ordinarily the female koi that holds the best results for body conformation.


Gin Rin Taisho Sanke First Place Winner
Gin Rin Taisho Sanke First Place Winner, Gin Rin A Division at 2011 Carolina Classic Koi Show

Color is about depth and is often likened to coats of paint. Vibrancy and intensity are great traits, but the color can’t be “thin.” The color has to be “thick,” healthy (not dull or with portions of discoloration that appear with movement) and uniform across the entire koi.

Color is affected by a few different factors like water condition, diet, genetic makeup, age, water temperature and even sex. Lighting can even have an effect on how the koi’s coloring appears, too. Shaded areas or electric lighting can mute the natural depth and luster.

Good skin condition from a slightly convex scale, as well as the characteristic reflective guanine, is a precursor to good coloration and is wrapped into the judging of color.


This essentially looks at how the colors are placed on the koi. The most critical feature is balanced in all directions—front to back and side to side. The color has to be sharp and crisp without bleeding into the other colors, with the pattern needing to be proportional across the koi. Being more prominent on one side versus the other will detract from the koi.

There are two types of pattern kiwa (“edge” or “side”) in appreciating pattern—the kamisori (razor) kiwa and maruzome (scalloped) kiwa. The edges of the razor edge have to be clean like linoleum blocks, whereas the scalloped has been alikened to that of a cherry blossom petal. This thread on koiphen offers some deeper insights into understanding the kiwa.

Also, there shouldn’t be any “windows” (small patches of other colors within bigger areas of color). And the pattern should be proportional to the size of the koi. Large koi should have large patterns, whereas smaller koi can have smaller patterns or it is considered inelegant or weak.

Quality and Elegance

This category is also sometimes called deportment. It is essentially the X-factor of personality and comportment, and is very much dependent on how the koi handles itself during the unfamiliar environment of the show on the particular day it is judged.

Judges will look at the koi’s orientation and overall appearance. Does it hold its fins close to the body? Does it swim erratically? Does it handle itself gracefully and draw attention to itself with its overall demeanor? Think of it like a Miss World contestant. Even though she might be drop-dead gorgeous, she can’t trip going up the stairs.

Imposing Presence

This is based on the judge’s first impression of the koi. This is also another fairly subjective judging category, as it is the “wow” of the initial viewing that can sway a koi judge’s scoring. It is another category that is dependent on how the koi presents itself on that particular day.

If you are thinking about entering one of your beauties into a show, consider going to one near you and see how they work. It is a great way to rub elbows with other koi enthusiasts as well as to see how shows are judged and what the winners look like.

At Next Day Koi, our koi for sale are sourced from some of the best suppliers in the industry. All our koi are quarantined in separate holding facilitates for a minimum two-week quarantine period, during which they are monitored for any signs of health issues.

Contact us to see how we can get your next koi fish to you with some of the industry’s most competitive shipping rates.

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