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  • Writer's pictureZiqi


Updated: Apr 17, 2020

What is Bonito Fish?

Bonito Fish is actually known as Skipjack Tuna or Striped Tuna. As the name shows, Bonito Fish is in a tribe of medium-sized predatory fish.

Bonito fish is also ray-finned, which also mean that they are boney-fishes.

Bonito fish belongs to the family of Tuna & Mackerels.

Similar fishes in the same family that are popular in the Japanese cuisine that are:

  • Bluefin Tuna / Hon Maguro (鮪魚)

  • Mackerel / Saba (サバ)

  • Horse Mackerel / Aji (アジ)

  • Pacific Saury / Sanma (さんま)

Is Bonito an English word?

You probably start wondering "Why is there so many names for Bonito Fish?" and "What exactly is the name?".

Nobody actually knows how the word "Bonito" comes about, whether it is even a legit English word. However, "Bonito" is now officially in the English dictionary as it is one of the most frequently used name for this particular fish. The official English name for "Bonito" is still known as Skipjack Tuna or Striped Tuna.

What's the difference between Skipjack Tuna and Striped Tuna?

Answer: There's no difference. There are just different names for the same thing.

Bonito Fish is also called as Katsuo (鰹/かつお) in Japanese; while it is known as chái yú (柴鱼) or mù yú (木鱼) in Chinese.

Skipjack Tuna Bonito Fish
Skipjack Tuna AKA Bonito Fish

Fun Facts of Bonito Fish

  • Streamlined fish

  • Dark blue to purple-colored back

  • Silvery bellies

  • Has about 3 to 5 horizontal stripes on the lower flanks

  • Almost has no scales except at the head area

  • Grow up to 80 cm long

  • Weigh from 8-10 kg

  • Lifespan of about 8-11 years

  • Can dive to 260 m depth during daytime

  • Swim near the surface of water during nighttime


How to Enjoy Bonito Fish?

There are many ways to enjoy Bonito Fish. However, I'm just gonna break down to 2 main categories on how Bonito Fish are being consumed or made into.

Katsuo no Tataki

Katsuo Sashimi Katsuo no Tataki Bonito Sashimi
Katsuo no Tataki

First of all, let's start from fresh. And by fresh, it of course means Sashimi!

Katsuo no Tataki refers to Katsuo Sashimi. It is a very popular dish found in Kochi, the southern coast of Shikoku, Japan. It is also one of the well-liked dishes at many restaurants and Izakayas.

However, as Bonito Fish carries a very strong fishy taste, instead of having it raw straight away to savor its freshness, Katsuo no Tataki has an unique way of preparation.

This is so as to allow those who are very intolerant of the fishy taste to enjoy Katsuo.

3 Important things to do before serving Katsuo no Tataki:

  • Sear the edges of the loin of Katsuo before slicing

  • Garnish with grated ginger, or garlic, before serving

  • Serve with Ponzu sauce, or any citrus-based sauce

Dried Bonito Fish

Dried Bonito fish / Katsuo boshi
Dried Bonito Fish

Next, which is also the most important and famous thing "Bonito Fish" is the Dried Bonito Fish.

Dried Bonito Fish is the main source to making:

  • Bonito Flakes / Katsuo Boshi (鰹節/かつお節)

  • Shredded Bonito Flakes / Ito Kezuri (糸けずり/糸削り)

  • Bonito Powder / Dashi no Moto (だしの素)


What is Dried Bonito Fish?

Dried Bonito Fish may be known as Katsuo to some, especially Japanese.

Therefore, when you are having a conversation about Katsuo with a Japanese, do make sure that you got the right idea of what they are talking about.

As they probably be referring to Dried Bonito Fish instead of the Bonito Fish itself.

So, now that you have seen the Dried Bonito Fish look, do you know how it turn out to become a small tube-like rock?

The dried Bonito Fish actually went through a long process of about 6 months to even a year or so. The process of making Dried Bonito Fish really helps to bring out the fragrance of it and that unique umami taste.

Process of making Dried Bonito Fish:

Step 1: Cutting of Bonito Fish
Boiling Bonito katsuo
  1. Behead the fishes

  2. Remove the vertebral bone of the fishes

  3. Slice up the body into 4 fillets

  4. Place the fishes neatly and evenly in a boiling basket

Step 2: Boiling the Bonito Fish
  1. Bring the basket of fish to boiling room

  2. They should be boiled just below boiling point (about 80 to 98°C) for around an hour to two*

* Boiling time differs according to the fish size

Step 3: Debone the Fishes
  1. After the boiling process is done, fishes are to be removed from the room & cooled.

  2. Tweezers are required to debone the remaining smaller bones on the fishes.

  3. The skin of the fishes should be soft enough to be scrapped off at this point of time.

Step 4: Smoking the Fishes
  1. Place the fishes neatly back on the basket

  2. Have your Oak, Pasania, Cherry Blossom and/or Castanopsis wood burning-ready for smoking.

  3. Smoke them for around 5 to 6 hours*

* Time differs according to the fish size

Step 5: Take a Break
  1. Let the fishes take a day off from the smoking process.

  2. Leave it at a cool dry place

Step 6: Repeat 4 & 5
  1. Bonito fish are not only smoked 1 or 2 times, it is to be smoked at least 12-15 times

  2. Whole smoking and break processes would take up to a month long

Step 7: Removing the Tar
  1. There should be tar built up on the fishes during the smoking processes.

  2. Tars are to be removed by grinding them

Step 8: Sun-dry the Fishes
  1. After removing the tar, fishes are to be left under the sun.

  2. They are to be sun-dried for about 2-4 days*

* Time differs according to the fish size

Step 9: Fermenting the Bonito
  1. Molds and fermentation products are applied to the bonito fishes

  2. Afterwhich, the fishes are left under the sun or fermentation room** for 2 weeks or longer

  3. The fermentation process will only be completed only when all the moisture are entirely removed from the fish.

** The place where fishes are process depends greatly on the manufacturing factory.

You may watch below video for better understanding of the process.

Do note that video is for illustration purposes only - different factories have different methods of making Dried Bonito Fish.

Credits to movie haradaizumi on YouTube for the video.

History of Dried Bonito Fish

Now that we have an rough idea of how Katsuo or Dried Bonito Fish is made, let's go onto the history of it.

It was shown in some sources that Katsuo Boshi, also known as Bonito Flakes, appeared in the late 1600s.

The most common story is of how Katsuo Boshi came about is:


There was once when a very brave soul, founded a moldy Katsuo Lying somewhere randomly, who decided to go on and taste it.

Afterwhich, he discovered this very umami flavor while having it.

As rumors started spreading, people started to go on making the molded Katsuo / Bonito and invented Dried Bonito Fish. However, people did not start fermenting the Katsuo back then.

It was until the 1700s, where some very good inventors tried fermenting the molded Katsuo, and unexpectedly discovered that it tasted even better and robust.


And then you could probably guess what happens after that...

All thanks to these great inventors back then, we are able to enjoy such umami flavors in many food.

Now that you've known about the rough idea of how Katsuo come about, it is also one of the lying results why different factories have a different processing method of Katsuo Boshi.

"" Disclaimer: This story is what was told and learnt and are based on different articles online.


Uses of Dried Bonito Fish

Knowing how Bonito Fish "transformed" to Dried Bonito Fish, let's see how it can be used after the transformation.

Katsuo Boshi (鰹節/かつお節)

Katsuo Boshi / Katsuobushi / Katsuoboshi / Katsuo Bushi / Dancing Bonito / Bonito Flakes / Fish Flakes
Katsuo Boshi

Katsuo Boshi is the main reason why people made Dried Bonito Fish this way.

They are also known as Bonito Flakes, which are shaved directly from Dried Bonito Fish.

Katsuo Boshi also has another name called as Dancing Bonito. The name comes about because when they are placed on top of a pipping hot dish, they will start to move or wriggle around, as if it is dancing on top of the dish.

Though they are thinly shaved, they are still very flavorful. It is not only flavorful itself, it also helps to bring out the flavors from many food. Thus, many Chefs are in favor of them.

Katsuo Boshi are often found on top on Okonomiyaki (Japanese egg pancakes) and Takoyaki Balls (Japanese Octopus balls).

ITO KEZURI (糸けずり/糸削り)

Ito Kezuri / Shredded Bonito Flakes / Katsuo Boshi
Ito Kezuri

Ito Kezuri refers to Shredded Bonito Flakes. It is actually the same thing as Katsuo Boshi, except it is thinner in width.

The use of it is similar, it is also often found on top Okonomiyaki and Takoyaki.

Other uses of Ito Kezuri will be that it is also often topped on vegetables or pickled dishes, like Takuan (Pickled Radish).

So, you may be thinking "What's the difference between Ito Kezuri and Katsuo Boshi?".

  • Ito Kezuri is usually the back or tail area of the dried bonito fish; whilst Katsuo Boshi is almost any part of the dried bonito fish.

  • Ito Kezuri is more expensive as it is harder to shred into thinner pieces; Katsuo Boshi is cheaper as it is bigger in size and packaging.

Dashi Soup / Dashi Stock

Dashi soup or Dashi Stock often refers to Fish stock. Dashi Stock is supposed to be a soup or stock which contain a strong umami flavor. In which, Dashi Stock is one of the main essential for cooking most of the Japanese dishes.

The most basic way of making Dashi Stock is by boiling water and add in a handful of Katsuo Boshi. Afterwhich, the Katsuo Boshi should be removed from the water, and the Dashi Stock is ready to be used.

Though Katsuo is full of umami flavor, it is not the only food that has that taste. Some other food that contain umami are:

  • Seaweed

  • Kelp

  • Mushroom

  • Seafood / Fishes

Thus, some may think that just adding only Katsuo Boshi may not have enough umami-ness to the broth; thus, Shiitake mushroom or Kelp (or both) are often added into the stock.

Ever heard of Vegetarian and Vegan Dashi? It is of course possible. Just boil Seaweed, Kelp and/or Mushroom, and the Vegetarian Dashi is ready.

Dashi no Moto (だしの素)

Dashi no moto / Katsuo boshi / Bonito powder
Dashi no Moto

Dashi no Moto refers to Bonito Powder.

Dashi no Moto can transform into Dashi Stock in less than a minute. Just by adding hot boiling water to it. Thus, it is also known as Instant Dashi Stock.

It is a very useful ingredient for many, especially those who are more lazy in kitchen, as we can skip the boiling of Katsuo Boshi and other ingredients.

Dashi no Moto comes in different flavors as well, where you can choose between whether you want to have kelp or mushroom and even the vegetarian option.

It is also a good replacement for anchovies stock or other fish stock.

Uses of Dashi no Moto / Dishes that requires Dashi no Moto:

  • Oyako Don / Chicken/Pork Katsu Don

  • Chawanmushi

  • Yaki Tamago

  • Miso Soup

  • Okonomiyaki

  • Udon or Soba Soup

  • Korean Army Stew

Mentsuyu (麺つゆ) / Tsuyu no moto (つゆの素)

Mentsuyu is also known as Tsuyu no Moto, where it is often used to make the soup for Soba and Udon.

Tsuyu no Moto is similar to Dashi no Moto, just that it comes in liquid form, and it has Soy Sauce mixed into the sauce.

It also comes in different flavors, in which the more commonly used one would be Tsuyu Kombu Sauce (昆布つゆ) - where Kelp was mixed into the blend.

Tsuyu no Moto and Tsuyu Kombu are also used to make the the cold dipping sauce for Cold Zawo Soba or Cha Soba.


Where to buy them in Singapore?

Jutrade / Dashi no Moto / Bonito Powder
Jutrade Dashi no Moto

You should be able to grab above mentioned items from those premium supermarket in Singapore. If not, you can contact us and find out more about the products or purchase from us directly from our website.

We do sell Katsuo Boshi, Ito Kezuri and Dashino Moto. You may click on below link or their names to direct yourself to their page.


Thanks all for today folks! Thank you so much for reading up this blog.

Please feel free to comments below if you have any queries regarding this post. And like us if you think these are very useful tips to you.

Till next blog post!

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