Your koi may already be the undisputed Grand Champion of your backyard… but how would it stack up in a real show ring? To find out, you need to think like a judge – and judges are looking at a lot more than “pretty colors” and “good vibes.”
Koi judging is a blend of science, art, and obsession. Judges don’t just see a fish; they see conformation, skin quality, pattern flow, color depth, and presence – all at once, in about three seconds, while the koi cruises past in a blue vat.
Let’s break down the main judging criteria in a fun, non-intimidating way so you can start seeing your koi the way the pros do.
1. The Big Picture: What Judges Actually Score
Most koi organizations use some variation of the same core pillars. Different groups weight them slightly differently, but the heart of it is the same:
- Body Conformation – shape, proportions, structure
- Skin Quality – luster, texture, purity of white, depth of color
- Color – intensity, consistency, and evenness of pigment
- Pattern – balance, placement, and flow of markings
- Overall Presence / Deportment / Elegance – how the koi “carries” itself
In many Japanese-style standards, conformation can count for roughly half of the overall evaluation, with quality and pattern making up most of the rest. Some Western clubs use point systems like 30% conformation, 30% color, 20% pattern, and the remainder for quality and presence. Either way, the message is clear:
A stunning pattern on a weak body will rarely beat a powerful body with a solid, if simple, pattern.
2. Body Conformation: The Foundation of a Champion
Conformation is koi-judge language for “Is this fish built correctly?” It’s usually the most heavily weighted category – especially as koi get large.
Judges look for a smooth, torpedo-shaped body that:
- Tapers gently from head to tail
- Is broad and powerful through the shoulders
- Has a thick, strong tail tube (the “engine” of the fish)
- Has fins in proportion to the body and evenly matched on each side
- Shows no deformities, kinks, bumps, or odd asymmetry
Think “elegant submarine,” not “lumpy sausage” or “pigeon-chested torpedo.” A koi with great conformation looks like it was designed for effortless, powerful swimming.
Age Matters
Judges also consider the koi’s age. Young koi can get away with being a little thin as they’re still growing, while mature koi are expected to have full, powerful bodies and strong frames.
3. Skin Quality: The Glow That Separates Good from Great
Skin quality is one of those things that’s hard to describe but impossible to miss. High-quality skin looks almost luminous – the white glows, and the colored areas appear rich and deep.
Judges examine:
- Shiroji (white ground): Should be clean, bright, and free of yellowing or stains.
- Scales: Uniform, slightly convex, reflecting light evenly.
- Luster: Metallic koi should shine like polished metal; non-metallic koi should still have a healthy sheen.
Two koi can have identical patterns, but the one with better skin quality will almost always win. Skin quality is like image resolution – the higher it is, the more breathtaking the fish.
4. Color: Depth, Consistency, and “Paint Quality”
Color isn’t just “red” or “black” – judges evaluate how solid, rich, and even that color is.
For example:
- Hi (red areas): Should be thick, even, and vibrant – not washed-out, patchy, or speckled.
- Sumi (black areas): Should be deep, lacquer-black, not gray or fuzzy.
- Shiroji (white): Forms the canvas that makes the other colors pop.
Good color looks like someone laid down smooth, expensive paint. Bad color looks like your printer ran low on ink halfway through.
Judges also expect consistency – the red on the head should match the red on the body in intensity and tone, and the black should be equally strong wherever it appears.
5. Pattern: The Design of the Fish
Pattern is what most new hobbyists notice first… and what most judges score after the body and quality. It’s still hugely important, especially within specific varieties.
Judges want patterns that are:
- Balanced: The koi shouldn’t look “front-heavy” or “tail-heavy.”
- Proportional to size: Big koi need bold, large patterns; tiny, fussy patterns can look weak on a jumbo fish.
- Variety-appropriate: A great Kohaku pattern isn’t the same as a great Showa pattern.
They’ll also look closely at:
- Kiwa: The trailing edge of a color patch – it should be sharp and clean, like it was cut with a razor.
- Sashi: The slightly blurred leading edge of a red pattern, ideally only one or two scales deep and evenly aligned.
A koi with a simple, well-balanced, and clean pattern can beat a wildly complex one that’s messy or poorly placed.
6. Overall Presence, Deportment, and “Wow Factor”
This is the most subjective but also the most fun category. Presence is how the koi feels in the vat. Does it command attention, or does it fade into the background?
Judges watch for:
- Calm, steady, confident swimming
- Fins held properly (not clamped or drooping)
- Alertness – not frantic, not half-asleep
- How the koi “fills” the vat visually
Two koi with equal technical merits can be separated by presence alone. The one that radiates “I am the champion” often… is.
7. Variety-Specific Standards: Not All Koi Are Judged the Same
Judges don’t compare a metallic Ogon to a three-color Showa using the same exact checklist. Each variety has its own ideal look and emphasis.
- Single-color metallic koi (like Yamabuki Ogon): With no pattern to evaluate, skin quality, body, and head cleanliness become everything.
- Gosanke (Kohaku, Sanke, Showa): Body and skin quality are king, but pattern is also heavily scrutinized for balance and refinement.
- Doitsu koi: Because they lack full scaling, any blemish or unevenness shows more. Judges expect clean, uninterrupted color and very sharp pattern edges.
So when a judge looks at a vat, they’re not just thinking “Is that pretty?” They’re thinking, “Is that pretty for this variety?”
8. How Criteria Change with Age and Size
Judging a 6-inch baby koi and a 30-inch jumbo adult isn’t the same game.
- Young koi: Pattern and potential often weigh more heavily; skin and body are still developing.
- Adult koi: Body conformation and skin quality dominate. By this stage, judges expect the koi to have “grown into” its pattern and finish.
This is why a koi that’s a rockstar at 2 years old may not stay competitive at 8 – and why some koi are “late bloomers” that only become truly breathtaking as adults.
9. Judging Organizations: Slightly Different Flavors, Same Core Ideas
Several major groups train koi judges and shape show standards worldwide, including:
- ZNA (Zen Nippon Airinkai) – the original Japanese koi organization, whose criteria heavily influence global standards.
- AKJA / AKCA, BKKS, KOI, and others – regional organizations that adapt and expand these standards.
Each may tweak scoring percentages, classification groups, or terminology, but they all circle back to the same pillars: body, quality, color, pattern, and presence.
10. Training Your Eye: How to Think Like a Judge (Without Being One)
You don’t need a name badge and a clipboard to benefit from judging criteria. Once you start looking at your koi through this lens, your appreciation for them deepens dramatically.
Next time you walk out to the pond, try this:
- Pick one koi and evaluate only its body shape – ignore color for a moment.
- Then look at just the skin quality – how does the white look in different light?
- Study the pattern from head to tail. Does it feel balanced?
- Step back and notice its presence. Does it draw your eye first?
Suddenly, you’re not just “liking” your koi. You’re understanding them – the same way a judge does, but with the added bonus that yours don’t have to beat anyone to be loved.
Koi judging isn’t mysterious magic – it’s a structured way of appreciating fish at a very high level. Judges look at body, skin, color, pattern, and presence, filtered through variety standards and age expectations.
When you learn the criteria, you don’t just prepare for shows – you unlock a deeper, more nuanced way of enjoying every single koi in your pond, Grand Champion or not.
Sources
- American Koi Judges Association. “Judging Koi.” AKJA Judges. (Accessed 2025).
- Koi Organisation International. “Bare Bone Basics of Koi Judging.” KOI.org, 2017.
- Washington Koi & Water Garden Society. “Judging Classifications.” WashingtonKoi.org.
- Inland Koi Society. “Koi Classification & Judging Criteria.” InlandKoiSociety.org.
- Zen Nippon Airinkai (ZNA). Official judging and judge guidelines, ZNA.jp and affiliated regional chapters.