We Filleted Loads of Whole Fish to Find the Best Deba Knives

Like breaking down a chicken, filleting a whole fish lets you see where that clean piece of meat comes from. And while it’s a messy business—guts, gills, and scales galore—it’s also often more economical—plus, you can use the bones and head for dashi and other dishes. 

While some folks prefer to use a bendy boning knife to swipe a filet off of a fish, when I was a prep cook at a restaurant, butchering whole fish was done with Deba knives. This stocky, Japanese knife is very different from a boning knife with its thick spine and single-beveled edge. But as Masaaki Saito, owner of Saito Knives in Brisbane, Australia, explains, this is what makes the Deba a truly multi-purpose knife.

“The biggest advantage of Deba knives over other European-style filleting knives is that everything can be done with one knife,” he says. “It is difficult to cut bones or fins with a skinny, flexible, filleting knife, as you will need a cleaver or scissors to work on any bony parts, while the pointy part of Deba knife can easily trim the flesh off the bones and the thick heel can halve the head, cut the bones into pieces, and remove fins.” That said, choosing and using a Deba knife requires some research—and maybe watching a few YouTube videos on how to use them.

To help get you started, we tested 10 knives by filleting fish big and small, spoke to experts, and even brought our favorites to a local fishmonger to try out. After all this testing, we found four offerings for experienced fish butchers and newbies alike. 

The Winners, at a Glance

The Best Hybrid-Style Deba Knife

Kai Seki Magoroku Kinju ST Japanese Deba Knife 150mm

$49 at Amazon

When it comes to agility, sharpness, and price point, this sturdy, hybrid stainless steel Deba has it all. We liked the angled handle, which made it easy to grip, though it was a bit large. 

Another Great Hybrid-Style Deba Knife

Fujiwara Kanefusa FKM Series No.3 Deba 150mm (5.9inch)

View on Japanesechefsknife.com

We loved the balance and heft of this knife, as well as its sharp stainless steel blade. The handle featured a pinched bolster, which gives you more control.

The Best Traditional Style-Deba Knife

Sakai Takayuki Kasumitogi Deba 150mm

$93 at Amazon

If you’re into carbon steel knives and are looking for a Deba that can tackle fish of all shapes and sizes, this is a great option. It sports a thicker, carbon steel blade (seven millimeters at its widest point) that decisively cuts through flesh and bone.

Another Great Traditional-Style Deba Knife

Tojiro Shirogami Deba #2 165mm

View on Chefknivestogo.com View on Chefknivesjapan.com

The biggest, heaviest knife in our lineup, the Tojiro was also super sharp thanks to its carbon steel blade. Its heft (it weighs a whopping 10.3 ounces) also helped it smoothly glide between the fillet and bones, ensuring a quick, clean cut. It was also surprisingly well-balanced. 

The Tests

• Blade Sharpness Tests: We used a professional blade edge tester to measure the sharpness of each knife out of the box.
• Fillet Smaller Fish Test: We used each Deba knife to gut and fillet a small sea bass. 
• Fillet Larger Fish Test (Winners-Only): We used each winning Deba knife to gut and fillet a large bluefish. 
• Fishmonger Use Test (Winners-Only): We had Natalia Gattuso of Fearless Fish Market in Providence, Rhode Island, use each of our winning knives to fillet scup. 
• Usability Tests: Throughout testing, we noted how easy the blades were to handle, maintain, and clean. 

What We Learned

Deba Knives Are Different Than Flexible Fillet Knives 

As Masaaki Saito, owner of Saito Knives, explained, unlike boning or filet knives, Deba knives are not only used to filet but also to cut through bone and clip off fins so the cook can use all parts of the fish. “Deba knives are designed for breaking down whole fish,” he says. “In Japanese cuisine, most parts of the fish are used to create different dishes. You'll find dishes like grilled snapper head, butterflied whole Alfonsino, or Grouper hot pot (with diced head, wings, and bones) served at top-end dining establishments. So chefs needed heavy-duty knives to cut through hard fish bones easily without damaging the edge.” And heavy-duty they are! Nearly all of the knives we tested had spines that were quite thick and heavy, with the Tojiro winning the prize for the thickest, heaviest knife with a 7-millimeter spine and 10.3-ounce weight. This heft and bulk is intentional and, as Saito noted, helps break through bone and ensures quick, clean cuts.

How to Use a Deba Knife 

Cutting fish with a Deba knife is slightly different than doing it with a filleting knife. While some filleting methods start by simply making a slit near the gills, the Deba method does this on each side, but then also removes the entire head. Once the head is removed, you can run the knife from the back of the stomach forward to open it and clean out the guts (if this hasn't already been done).

Once that’s done, use the knife to gently cut along the interior of the spine and wipe it out. Then, start filleting by running the blade down from the belly towards the tail, flip the fish over, and run the blade (slightly angled) along the top of the fish from the tail to the head. Now, swipe the knife gently between the spine bones and the flesh—you should hear a scraping sound where the blade is cutting the fish away from the bones. Do the same on the underside of the same side, then separate the filet by cutting through the flesh near the tail. Repeat on the other side. 

A Sturdy Grip Was a Must

Filleting fish is a messy, slippery business, so while a grippy handle might seem like something of little importance, we found it incredibly helpful. Most of the Deba knives we tested had rough wood handles that made them easier to grip. However, the Kai Wasabi Deba Knife had a rounded, plastic handle that got really slippery during filleting, which isn’t ideal when you’re wielding a heavy-duty, sharp knife. Gattuso also found handles that narrowed slightly towards the bolster, like on the Sakai Takayuki Kasumitogi Deba 150mm, were easier to grip and control. 

Experience Level Mattered

If you’re new to Deba knives, you might want a smaller, softer knife, which is less likely to chip and easier to maintain and use. “For beginner users, hybrid ones may be easier to maintain because of the easy maintenance and more forgiving characteristics, while the white carbon steel ones can rust easily and chip easily, but have much better sharpness and edge retention when used properly,” Saito says. He also suggests looking for knives with shorter blades, 150 to 180 millimeters (around six to seven inches long). If you’re more confident filleting fish, have used a Deba knife before, and are used to Japanese-style blades, a longer, carbon steel blade could be a good choice. 

Fish Size Was Also Important

If you’re filleting sardines or other small fish, a big, hefty Deba might be tricky to use without mashing. Conversely, if you’re filleting a roughly 24-inch bluefish (like we did), a thicker, hefty blade can make quick work of removing the head, gutting, and filleting. Saito gave us a general idea of Deba to fish sizes: 

Our Favorite Knives Were Balanced, Sharp, and Multipurpose

While most of the knives we tested were incredibly sharp out of the box and performed well, our favorite knives were more versatile in terms of size and had a balanced blade and handle. When it came to the more traditional style Deba with a carbon steel blade, we really liked the Sakai Takayuki, which had a 150-millimeter-long blade (around six inches long), a grippy wooden handle, and a balanced feel. The hefty Tojiro was also great, balancing weight with sharpness and agility. Both of these knives excelled at fileting fish big and small. While the white steel Okeya Deba was also quite sharp, it was really small and light, with a five-inch-long blade and a mere 3.5-ounce weight—it’s probably better suited to filleting smaller fish or even mincing scallions or other tender vegetables. When it came to hybrid knives, that is, knives that are made of stainless steel and hence softer, we also preferred mid-sized knives; among our favorites were the kai Seki Magoroku Kinju ST Japanese Deba Knife and the Fujiwara Kanefusa FKM Series No.3 Deba, both of which had easy-to-grip handles, and balanced and sharp 6-inch blades; they tackled larger fish as easily as they did small scup. 

The Criteria: What to Look for in a Deba Knife 

We recommend looking for a versatile Deba knife with a blade that is 150 to 180 millimeters (roughly six to seven inches) and has enough heft to cut through bone and quickly cut flesh away. It should also have a grippy handle that won’t get slippery or slick when wet.

If you’re nervous about sharpening knives or have never used a Deba, a hybrid stainless steel model might be the best choice in terms of maintenance (they’re also less likely to chip). If you’re an old hand at filleting fish, a high-carbon steel blade offers a refined edge and quick, biting cuts. And if you’re left-handed, make sure you choose a knife that offers an option to have the single-beveled edge switched to the left side (though this may have to be done via special request). 

The Best Deba Knives 

The Best Hybrid-Style Deba Knife

Kai Seki Magoroku Kinju ST Japanese Deba Knife 150mm

$49 at Amazon

What we liked: With a balanced 6-inch blade and faceted handle, this weighty knife filleted and cut through bone with ease. The stainless steel blade is less work to sharpen and maintain, making it a great choice for beginners or those who are intimidated by carbon steel knives. It’s a great bang for your buck.

What we didn’t like: Since it’s stainless steel, it likely will dull a tad faster than a carbon steel blade. Gattuso also found the handle a bit large.

Key Specs

• Handle length: 4.75 inches
• Blade length: 150 millimeters (6 inches)
• Spine thickness: 5 millimeters at widest point
• Weight: 8.6 ounces
• Materials: Molybdenum vanadium stainless steel, composite handle
• Sharpness reading average: 65 (double-edged razor-blade sharp)
• Cleaning: Hand-wash and dry

Another Great Hybrid-Style Deba Knife

Fujiwara Kanefusa FKM Series No.3 Deba 150mm (5.9inch)

View on Japanesechefsknife.com

What we liked: While it had a more Western shape, this hefty knife cut through bone easily and swiped fillets off without a hitch. We liked the smooth but angled handle, which didn’t get slippery even when we butchered a large (and quite bloody) blue fish. And since it sports a stainless steel blade, it’s easier to maintain. “It has a good medium weight, and I like the bolster,” said Gattuso. 

What we didn’t like: Since it’s stainless steel, it’s likely to lose its sharp edge faster than a carbon steel blade (though that is easily remedied by honing and sharpening it).

Key Specs

• Handle length: 4.5 inches
• Blade length: 150 millimeters (6 inches)
• Spine thickness: 4 millimeters at widest point
• Weight: 9.1 ounces
• Materials: Molybdenum Vanadium stainless steel; black pakkawood handle with stainless steel bolster handle
• Out-of-box sharpness reading average: 58 (double-edged razor-blade sharp)
• Cleaning: Hand-wash and dry

The Best Traditional-Style Deba Knife

Sakai Takayuki Kasumitogi Deba 150mm

$93 at Amazon

What we liked: With a 7-millimeter thick carbon steel blade, this knife has it all: weight and sharpness. It tackled smaller sea bass and scup just as easily as larger fish. “It’s really smooth and steady," said Gattuso. "It’s also balanced and still small enough to maneuver around the spine.” We also liked the grippy wooden handle. 

What we didn’t like: If you’re new to Japanese-style knives, the carbon steel blade is a little bit more work to maintain (and if you’re new to filleting fish, it’s less forgiving and more brittle than stainless steel).

Key Specs

• Handle length: 4.75 inches
• Blade length: 150 millimeters (6 inches)
• Spine thickness: 7 millimeters at widest point
• Weight: 7.8 ounces
• Materials: White steel carbon steel; Magnolia wood handle
• Out-of-box sharpness reading average: 57 (double-edged razor-blade sharp)
• Cleaning: Hand-wash and dry

Another Great Traditional-Style Deba Knife

Tojiro Shirogami Deba #2 165mm

View on Chefknivestogo.com View on Chefknivesjapan.com

What we liked: This was the heftiest knife we tested, making it a great option for filleting larger fish since the weight of the blade helps it slice quickly; it was also super sharp. The rough wooden handle was also nice and grippy. 

What we didn’t like: Since it has a wooden handle and carbon steel blade, it should be thoroughly dried after washing and we’d advise rubbing the handle with some food-safe mineral oil. It’s also quite heavy, though Gattuso was able to easily fillet smaller scup with it. “For being so heavy, it’s surprisingly balanced and easy to control,” she said. It’s on the pricier side of the lineup of knives we tested, though we still think it’s a good deal for a great knife. 

Key Specs

• Handle length: 5 inches
• Blade length: 165 millimeters (6.5 inches)
• Spine thickness: 7 millimeters at widest point
• Weight: 10.3 ounces
• Materials: White #2 steel with soft iron cladding; Magnolia with black resin Ferrule handle
• Out-of-box sharpness reading average: 140 (utility razor blade sharp)
• Cleaning: Hand-wash and dry

The Competition

• Kai Wasabi Deba Knife 6": While this knife was actually pretty good in terms of heft and sharpness, we found the rounded plastic handle got really slippery during use and cleaning. 
• Global Deba Knife, 4.75: While this was a somewhat sharp knife, it really was too small and thin to cut through bone. Plus, the metal handle got quite slippery when filleting fish. 
• Mercer Culinary Asian Collection Deba Knife, 6-inch: The lightweight stainless steel blade meant this Deba wasn’t quite as sharp or effective as other knives we tested. 
• Kanetsugu Hybrid Wa Bocho Series Deba: This knife, while visually stunning, had a top-heavy blade that threw off its balance. Yet, even though it felt heavy in the hand, it struggled to cut through smaller scup bones. 
• Okeya White #2 Ko-Deba 120mm: While this is a pretty little knife, we found ourselves wanting to use it for things other than filleting fish. “It’s adorable,” said Gattuso, “I want it as a vegetable cleaver.” It weighed a mere 3.4 ounces, lacking the heft that helps slice through fish and cut through bone. 
• Mac Knife Japanese Series 5-1/2-Inch Deba Knife: We liked the French bolster on this knife, which was sturdy and easy to clean. However, the knife itself felt a little clunky and unbalanced.

FAQs

What is a Deba knife?

A Deba knife is a Japanese fish fileting knife. It differs from Western-style filet or boning knives in that it’s often quite thick and heavy, and is meant to cut through bone as well as flesh. 

What is a Deba knife used for?

These thick, heavy knives are used to break down whole fish. Their stockiness helps them cut through bones. 

Can you use a Deba knife for everything?

While you can use a Deba to cut other foods, like chicken or vegetables, it’s not recommended to use them for really thick bones or hardy vegetables, especially if they are carbon steel, since this can damage the blade. 

What's the difference between carbon steel and stainless steel knives?

In short, carbon steel knives stay sharper longer—but they have a brittle edge that requires more maintenance (e.g. thoroughly drying the blade and rubbing it with Tsubaki oil to keep it rust-free). Carbon steel is also more prone to chipping if used incorrectly (you can read more about carbon steel blades here). Stainless steel knives tend to dull faster, though they are more durable and can be honed and sharpened back into shape more easily.

Why We’re the Experts

• Grace Kelly is the associate commerce editor at Serious Eats. 
• Prior to this, she tested equipment and ingredients for America’s Test Kitchen. She's worked as a journalist and has done stints as a cook and bartender. 
• She has written dozens of reviews for Serious Eats, including petty knives, tinned fish, fish spatulas, and tortilla presses, among others. 
• We reviewed 10 Deba knives by using them to fillet small hybrid sea bass. We also used our winning picks to fillet a 24-inch bluefish and had Natalia Gattuso of Fearless Fish Market in Providence, Rhode Island use the knives to fillet scup. 
• We interviewed Masaaki Saito of Saito Knives in Brisbane, Australia, to get background on Deba knives. Saito is a former fish butcher and sushi chef, who now makes and sharpens knives.