EMS codes are everywhere in our world.
They appear on pedigrees, in show catalogues, in judges’ reports, and in everyday communication between breeders and judges. We use them constantly, often without hesitation, and we rarely stop to question whether we truly understand what they represent.
At first glance, the system feels simple. A structured combination of letters and numbers that seems to describe a cat precisely and objectively. In many ways, that impression is correct. EMS was created to standardize the description of cats and to enable clear communication across breeders, judges, and registries.
But the simplicity is, to some extent, an illusion.
Because EMS does not describe what a cat is. It describes what we see.
This is not the first time that a system appears clear on paper, yet becomes complex in practice. As discussed in The Problem Is Not the Standard — It’s How We Read It, the challenge is often not in the rules themselves, but in how we interpret them. The same applies when descriptions begin to replace understanding, a pattern already explored in When the Market Starts Designing the Breed.
Phenotype Is Not Genetics
This distinction is fundamental, and yet it is often overlooked in practice.
This essay is also available as a short video lecture. The full written version continues below.
TEMS codes are based on phenotype — on visible traits such as color, pattern, and the distribution of white. They do not describe hidden genes, they do not predict breeding outcomes, and they do not replace genetic knowledge.
EMS describes what is visible. Genetics explains what is possible.
However, in everyday use, EMS is frequently treated as if it carries genetic certainty. A code becomes a label, and that label is often perceived as a complete definition of the cat. This is where misunderstandings begin.
Two cats may share the same EMS code while being genetically different, and two cats may appear different while carrying the same genetic foundation. EMS does not resolve this complexity. It simply records a moment of interpretation.
Where Interpretation Begins
Even when the structure of EMS is clear, interpretation is unavoidable.
A code follows a logical order — breed, color, pattern, and additional information — and examples such as NFO n 22 appear straightforward. Yet, the moment we move from theory to real cats, the system becomes less absolute.
Consider silver. In some cats it is clearly visible, while in others it is subtle or almost impossible to detect with certainty. And yet, breeding results may reveal its presence beyond any doubt. The question then becomes unavoidable: do we code what we see, or what we know?
This becomes particularly evident when comparing codes such as BRI ns 11 and BRI ny 11. The visual difference between silver shaded and golden shaded may, in some cases, be extremely subtle. Warm silver may be mistaken for golden, and golden may be described as a low-contrast silver. In such situations, EMS is no longer a simple description, but an interpretation influenced by experience, expectation, and sometimes even assumption.
The same applies to tabby patterns. The distinction between mackerel (23) and spotted (24) is not always clear-cut. A Siberian coded as SIB n 23 may, in reality, show broken stripes approaching SIB n 24. There is no exact moment when one pattern becomes the other. The decision is made by the person evaluating the cat, not by the system itself.
When the System Meets Reality
The challenges do not end with color and pattern.
White patterns introduce another layer of complexity, as they are also evaluated phenotypically and not genetically. A combination such as MCO n 09 22 may appear straightforward, yet the actual distribution of white can vary significantly, influencing how the pattern is perceived and coded in practice.
Even seemingly simple cases can raise questions. A white Persian coded as PER w 62 (blue eyes) may visually appear clear and consistent, yet the underlying genetic background may be more complex than the code suggests.
These examples illustrate a broader point: EMS operates at the intersection of observation and knowledge. It is neither purely objective nor purely subjective. It is a structured interpretation of what is visible.
And this is precisely why EMS cannot be used in isolation.
Why Genetics Still Matters
To use EMS correctly, a basic understanding of genetics is essential.
Genetics defines what is possible. EMS only describes what is visible. When these two aspects are aligned, the system functions well. When they are not, inconsistencies begin to appear.
A simple example illustrates this clearly. Two cats coded as a (blue) cannot produce a kitten coded as n (black).
If such a result appears in a pedigree, the issue is not with genetics, but with the interpretation or recording of the parents.
This is not a rare situation.
It is a reminder that EMS does not override biological reality. It depends on it.
Common Mistakes and Their Consequences
In practice, many EMS-related errors are not the result of a lack of rules, but of how those rules are applied.
Codes are sometimes assigned based on approximation rather than careful observation. Numbers may be placed in the wrong order, or chosen simply because they appear “close enough,” without considering whether the standard actually supports that interpretation.
In practice, one of the most common mistakes is not misunderstanding EMS — but simply copying it from the pedigree without re-evaluating the cat.
Over time, these small inaccuracies accumulate. What begins as a minor inconsistency can develop into a systematic problem, affecting pedigrees, breeding decisions, and ultimately the understanding of entire lines.
A Familiar Pattern
This situation should sound familiar.
We have seen the same pattern in how standards are interpreted. The problem was never the standard itself, but the way it was read and applied. EMS follows the same principle.
The system is not the problem.
Our understanding of it is.
When Codes Start Driving Decisions
There is also a broader implication that is becoming increasingly relevant.
Certain EMS combinations gain popularity. They become desirable, marketable, and sought after. Codes such as golden variations or specific shaded patterns are not only descriptions anymore — they are becoming targets.
Over time, this can shift the focus from the cat itself to the code that describes it.
Breeding decisions may then be influenced not by the overall quality of the cat, but by the combination of letters and numbers associated with it. This is a subtle shift, but one that can have long-term consequences for breeds.
It is the same mechanism we have already seen before.
Only now, it operates through codes.
What EMS Should Be
EMS was never meant to define cats.
It was designed to describe them.
It is a language — a tool that allows us to communicate what we see in a consistent and structured way. It does not replace observation, it does not replace experience, and it certainly does not replace genetic understanding.
Using EMS correctly means recognizing its limits.
It means describing what is visible, applying the rules consistently, and questioning results that contradict basic genetic principles. It also means accepting that behind every code there is a decision, and that decision carries responsibility.
Beyond the Code
In the end, EMS is only a system.
It can organize information, but it cannot replace judgment. It can support communication, but it cannot ensure understanding.
What matters is not how accurately we write the code, but how well we understand the cat behind it.
Because we are not working with letters and numbers.
We are working with living animals.
And no system, no matter how structured, can replace the responsibility that comes with that.
Written by Trpimir-Frane Sulić
President of Felis Croatia (KMFC)
WCF Judge
