Japanese knife blade length is measured in a straight line from the tip to the machi, the notch where the blade steps down into the handle. The handle isn't counted, so a 210mm knife is longer overall. To check your own, lay it flat and run a ruler along the spine, the dull top edge.
At a glance
- Not sure what to buy? A 210mm gyuto, the Japanese chef's knife (about 8.3 inches), suits most home cooks.
- Blade length runs from the tip to the machi, where the blade meets the handle. The handle isn't counted.
- Sizes are approximate. Japanese knives are handmade, so a 210mm knife can measure a few millimeters either way.
- Our listings state blade length. Other makers can differ slightly, so check how a length is stated before comparing brands. Unsure which size? Email info@echefknife.com before you order.
How to Measure a Japanese Knife's Blade Length
- Lay the knife flat on a table with the edge facing you.
- Line up the zero mark of a ruler with the very tip of the blade.
- Run the ruler along the spine in a straight line, not following the curve of the edge.
- Read the number at the machi, where the steel stops and the handle begins. If a ferrule or bolster hides it, measure to where the steel disappears into the handle. That's your blade length.
Expect it to be close to the listed size, not exact. Japanese knives are handmade, so a 210mm knife may measure a few millimeters over or under, and that's normal.
Is Blade Length Measured With the Handle?
No. Japanese knife sizes describe the blade only, so a 210mm gyuto is longer overall. With its handle, it's typically 320 to 350mm. The same rule applies to single-bevel knives like the yanagi and deba: tip to machi, handle not included.
Why Japanese Knife Sizes Are Rounded Numbers
Japanese knife sizes originally came from the sun, a traditional unit of about 30.3mm. Today makers work in metric, but the traditional sizes live on as rounded numbers: 180mm is about 6 sun, 210mm is 7, 240mm is 8, 270mm is 9 and 300mm is one shaku (10 sun). A knife sold as 270mm is really closer to 273mm, and we list the rounded number.
In inches, 210mm is about 8.3 and 240mm is about 9.4. A Western 8-inch chef's knife is close to a 210mm gyuto, and a 240mm is a step up.
What Size Japanese Knife Should I Buy?
- Most home cooks, and a first Japanese knife as a gift: a 210mm gyuto or a 165 to 180mm santoku covers nearly everything.
- Small boards or small hands: go down to 165 to 180mm. It's quicker and easier to control. Many santoku and nakiri come in just one size, so check the size options on the product page.
- Big boards, large roasts, or professional kitchens: 240mm and up gives you a longer stroke.
- Slicing fish or roasts: a 270 to 300mm yanagi or sujihiki lets you cut in one long pull.
Still not sure? Start with a 210mm gyuto. Whatever you pick, make sure the blade is comfortably shorter than your cutting board. New to Japanese knives? Our complete guide to Japanese knives covers every style.
Why Brands Don't Always Match
Our listings state blade length, tip to machi. Other makers may not: some include part of the handle, and Western knives are often sized from the bolster to the tip. The same number can describe a meaningfully different knife, so before comparing sizes between brands, or between Japanese and Western knives, check three things:
- Is the number the blade length or the overall length?
- Does it stop at the machi, or include part of the handle?
- Is the cutting edge length listed separately?
Frequently Asked Questions
What is the machi on a Japanese knife?
The machi (区) is the notch where the blade steps down into the tang, the part that sits inside the handle. Blade length is measured from the tip to the machi.
What is the heel of a knife?
The heel (ago) is the rear corner of the cutting edge. It sits just in front of the machi.
How many inches is a 210mm gyuto?
A 210mm gyuto has a blade of about 8.3 inches. A 240mm gyuto is about 9.4 inches.
Should I buy a 210mm or 240mm gyuto?
Choose 210mm if you cook at home or work on a standard board. Choose 240mm if you regularly break down large proteins or have the board space for a longer blade.
Why is my knife's cutting edge shorter than its listed size?
Blade length is measured to the machi, but the sharpened edge ends at the heel, a little earlier. How much earlier varies from knife to knife, because each one is handcrafted and ground by hand. It's often 5 to 15mm, and that's normal.
Need Help Choosing a Size?
If you're not sure what length fits how you cook, email us at info@echefknife.com before you order. We're glad to help.
