Koi Varieties - Kohaku

The Kohaku (koh-HAH-koo) variety of koi is the first subcategory of the larger category Gosanke discussed in the last blog post found here: kerutokoi.com/post/koi-variety-gosanke As mentioned, a Kohaku fish has a solid white base (shiroji) that is overlaid with red (hi) colouration.

Kohaku Koi
Kohaku from breeder Maruhide

Kohaku are a very popular koi variety. Not only are they one of the most traditional koi and a type of Gosanke koi, but they are also often a koi-keepers first variety of koi. Even non-koi enthusiasts will recognise the distinct colouration of this incredible variety. It is this that gives the Kohaku the nickname ‘The King of Koi’. But what distinguishes a good Kohaku from a bad one?

The four things you need to look at when judging a Kohaku are the body, colour quality, pattern, and breeder. Let us consider each of these in turn:

Body Shape

Firstly, the body is often the most important factor in a good koi fish. In fact, in most koi competitions, up to half of the points available are given purely for the body and its conformation to the ideal shape. Size is not as important because a good body shape in a small koi is a very good indication of a good body shape when the koi is fully grown. A good body shape is typically described as a tree trunk, so not too thin but also not so large that the fish looks bloated. Ideally, the koi will look strong and muscular rather than fat and overweight. Obviously, a good koi will have no deformities such as a crooked body or missing fins. Finally, the best koi will also have a large, symmetrical head and a thick tail joint.

Colour Quality

Next, you need to consider the colour quality of the koi fish. Specifically, you need to check three things, the ‘shiroji’, the ‘hi’, and the ‘kiwa’. ‘Shiroji’ refers to the white base and it should be a lovely snow white with no pink areas. Then, ‘hi’ refers to the red colour. The actual shade of red is not as important as the consistency, the koi should have the same shade of red all over, but a bright, vibrant red is best. Lastly, ‘kiwa’ refers to the edges. Ideally, a koi should have strong, sharp edges with a clear distinction between the red and white colours. Any colour bleeding of the red into the white areas is not desirable, similarly, a white spot inside an area of red is not ideal.


The next consideration is of the pattern itself. The red colouration should begin at the head of the fish, move down the body, and stop at the tail. The tail and the fins should be white while most of the red colour should be on the top of the fish as most koi are viewed from the top. The best Kohaku have multiple, separate areas of red, known as steps, going down the length of the fish. A stepped pattern is always considered best, with the value of the koi increasing with the number of steps up to five steps. The value stops at five steps because if a Kohaku has more than five steps, then the steps themselves are too small in relation to the body. This only applies to traditional Kohaku, there are many other types of Kohaku, we will discuss one below, where a different type of pattern is more desirable.


The final thing to consider when judging the quality of a Kohaku, especially a young Kohaku, is the breeder. A koi can change a lot over its lifetime and if you are buying young fish, the only way to ensure that you will end up with a good quality adult fish is to know the breeders and buy from the right breeders. The breeders have the most knowledge and experience when it comes to selecting the best koi and the right breeders will only import young koi if they know that the fish will be of the best quality. Unfortunately, it is no longer good enough that the koi come from Japan, there are many newer breeders who are less fussy with the fish that they send to the UK meaning that it is especially important to do your research on the breeder. All of the fish we stock at Keruto Koi are from reputable breeders so you can be ensured that your koi will remain good quality throughout its lifetime.

So, know you know how to tell a show-winning Kohaku from an average Kohaku. Have a look at our website for our current stock of Kohaku.

Let us briefly mention another Kohaku variety that is commonly kept but differs from the rules set out above:

Tancho Kohaku
Tancho Kohaku from breeder Marudo

Tancho Kohaku

The Tancho Kohaku is a popular variety of Kohaku koi, but it is often difficult to find the best quality Tancho koi. This koi is a type of Kohaku as it has a white base with a red pattern, but it differs from a normal Kohaku as it has only one step and this step is positioned on the head of the koi. This variety is very highly sought-after as it is often compared to the Japanese flag. However, the variety is often one of the more expensive varieties, especially for the best quality Tancho, as the breeding process is very unpredictable and therefore many Tancho koi do not have a clear spot on the head or the spot itself is not very round and circular or is too large for the head.

Look out for our next 'Koi Varieties' article,