Kazunoko (数の子), or salted herring roe, is one of the popular dishes in Osechi Ryori (おせち料理), the Japanese New Year food. Marinated in soy dashi seasoning, this rare and expensive delicacy is considered an important part of Osechi as it symbolizes many children and a prosperous family,

What is Kazunoko?

Kazunoko (数の子) is salted herring roe. As a child, I wasn’t particularly fond of this dish and I wondered why my parents enjoy this salty weird-texture food. As I got older and gained more experience in eating different textures and flavors of foods, I started to enjoy this delicacy more. Each roe is a collection of tiny eggs and it has a beautiful golden color. As you bite into it, it gives a crunchy texture (the texture is explained as kori kori コリコリin Japanese). The tiny eggs break apart from each other and disintegrate inside your mouth. The individual eggs have a caviar/tobiko-like texture. In terms of its flavor, kazunoko has an acquired taste. There’s saltiness, and you can also taste umami from dashi and soy sauce base seasoning after it’s marinated.

3 Things You Need To Know Before Cooking Kazunoko

1. Need to desalinate in saltwater.

This might sound strange. Why do you desalinate (remove salt) salted herring roe with salt water? There are also some recipes that ask you to soak in plain water to desalinate. So which is correct? Well, the correct way can be explained by chemistry… When you soak in plain water, there is too much difference with the salt concentration and you will lose salt content too quickly as well as the umami of the eggs. The salinity contains sodium chloride and magnesium chloride and they have different dissolving rates (sodium chloride dissolves faster and magnesium chloride dissolves slowly). If you soak it in plain plater, it means that sodium chloride will dissolve first and magnesium chloride will remain in the roe and give the roe an unwanted bitter taste. In order to remove magnesium chloride, it must be further soaked in water and it will make the kazunoko lose all the umami flavor and become watery. If you use salt water, the difference in concentration decreases and the salt slowly escapes. Only excess salt will be removed while moderate salt content and umami remain in the herring roe.

2. Gently remove the membrane

The only drawback of preparing kazunoko is the tedious peeling process of herring roe membrane. If you don’t remove this membrane, the dashi and seasonings won’t be absorbed well. Once the membrane is removed, kazunoko looks much prettier in color too. So be ready for this time-consuming process, especially if you have to make a lot of kazunoko… My quick tip is to use your thumbs to press the membrane upwards against the center of the roe. Once the membranes are collected in the center, you can pull up from the edge and detach from the roe easier.

3. Use Usukuchi Soy Sauce

If possible, I recommend using Usukuchi Soy Sauce (薄口醤油). It’s a light-colored Japanese soy sauce, commonly used in western and southern Japan as the main soy sauce. Even though it’s called light-colored soy sauce, it is actually saltier than dark-colored Koikuchi Soy Sauce (濃口醤油). As I grew up in the Tokyo area, my “regular” soy sauce is Koikuchi and I don’t keep Usukuchi soy sauce in my kitchen. I used to keep both, but since I rarely finish up usukuchi soy sauce before the expiration date I stopped purchasing them. The good reason why you should use usukuchi soy sauce for this recipe is to keep the ingredient’s beautiful golden color. The dish also won’t look as dark if you use usukuchi soy sauce. Other dishes I recommend using usukuchi soy sauce are nimono (simmered dishes) like Chikuzenni and Chawanmushi (savory steamed custard).

Where To Find Kazunoko

Your local Japanese grocery stores may start to sell kazunoko (salted herring roe) shortly after Christmas. During this time, the grocery store will focus on Osechi Ryori ingredients and New Year celebration produces and products. At my local Japanese grocery store, kazunoko usually costs about $25 to 30 per pound. I’m not familiar if other Asian cuisines use salted herring roe. If you have purchased and used this in your cuisine, let me know in the comment below where you purchased it from. Kazunoko is usually prepared and enjoyed once a year for the New Year’s feast. Ingredients used only for a special holiday like this can be difficult for us living outside of Japan to acquire. I apologize if you can only read and learn about this dish, and can’t make it for yourself due to the availability of the ingredients. Wish to learn more about Japanese cooking? Sign up for our free newsletter to receive cooking tips & recipe updates! And stay in touch with me on Facebook, Pinterest, YouTube, and Instagram.