Japanese Knife Sharpening and Maintenance Guide

japanese knife sharpening, Japanese Knife Sharpening and Maintenance Guide

There is nothing worse than a dull knife.

Or a chipped knife.

Or a rusted knife.

Or…

Well, you get the point.  Once you lay down some big bucks on a beautiful Japanese knife, you’re going to want to take care of it.

Knowing how to correctly maintain and sharpen your blade will not only make it more effective, but will also prolong its useful life and give you many years of loyal service.  

In this guide, I will go over some basic knife maintenance tips, as well as a step by step outline on how to sharpen your Japanese knife.

General Knife Maintenance and Usage

Washing / Drying

japanese knife sharpening, Japanese Knife Sharpening and Maintenance GuideYou should always hand wash, and hand dry your knife (don’t forget the handle).  Never put it in the dishwasher.   Some entry-level knives will say they are “dishwasher safe”, but I think it is best to get in the habit of hand washing and drying.  Simply use a soft sponge, some dish soap, and hot water.  If you put the knife in a dishwasher, there is also a chance it will rattle around and damage the cutting edge.

Many high-carbon steel knives will rust, or discolor very quickly if left wet, ruining your beautiful knife.  Therefore, it is also smart to have a towel on hand that you can use to quickly wipe off moisture as you prep food.

Usage

Never try to use your Japanese knife to cut through hard bone, or hard surfaces.  Japanese blades are made from very hard steel (60+ HRC) which allows it to retain a sharp edge for a long time, but also makes it more brittle.  They are also much thinner, with a more acute cutting edge than a typical Western-made knife.  This further increases the potential of chipping if used incorrectly.

When talking about steel, “hardness” is very different from “toughness”.  Hardness refers to the ability to withstand penetration, or scratching  (e.g. a diamond is super hard).  Toughness refers to the material’s ability to absorb energy, or withstand a fracture.  As hardness increases, toughness decreases.  For example, Western made knives use softer steel (55~58 HRC) which will dull more quickly than Japanese knives, but are “tougher” and less likely to chip.  Knife makers are constantly trying to find a good balance between the two properties.

japanese knife sharpening, Japanese Knife Sharpening and Maintenance Guide

You also need to be using proper cutting technique.  This means using a smooth cutting motion, and not exerting an excessive amount of force to drive your knife down into the cutting board.  If you find yourself using lot of strength, either your knife is not sharp enough, you are using the wrong type of knife, or you are trying to cut something that you should not be.

Cutting Boards

Your cutting board should not be so hard that it damages your blade.  Hi-soft (polyvinyl acetate), or end-grain wood boards are the most recommended cutting board materials.  All-rubber / Sani-tuff boards are also good.  If you are on a tight budget, you can get a cheap soft plastic (polyethylene) board, but they tend to scratch easier and are more difficult to clean.

japanese knife sharpening, Japanese Knife Sharpening and Maintenance Guide

Whatever you do, avoid cutting boards made of hard materials like bamboo, granite, stainless steel, hard plastic or edge-grain wood that will dull or damage your knife edge quickly.

Storage 

Day to day

After cleaning and drying your knife, there are a few options for day to day storage.

  • Magnetic Strip – You can mount it on your wall, or fridge.  This is a great, and cheap option for smaller kitchens, as it can save a lot of that precious counter space.  The only issue is that it does not offer any blade protection, but this shouldn’t be a problem if you pick a good spot that avoids anything banging into your knives.
    japanese knife sharpening, Japanese Knife Sharpening and Maintenance Guide
  • Knife Block – The good ol’ knife block.  Comes in many styles and designs.  Usually made of wood.   It looks great, and also protects the blade, BUT, it can take up valuable counter space.  Make sure you buy one that is tall enough for your knives, and is “universal”, meaning you can insert knives anywhere in the block.japanese knife sharpening, Japanese Knife Sharpening and Maintenance Guide
    japanese knife sharpening, Japanese Knife Sharpening and Maintenance Guide
  • In a drawer – There are also some knife blocks / inserts that that fit within a drawer.  Great if you have an extra drawer to use.  If you are just putting your knife loose in a drawer, make sure you use a sheath or blade guard to protect the knife (and your fingers when reaching in).
    japanese knife sharpening, Japanese Knife Sharpening and Maintenance Guide
Travelling

Some people like to travel with their knives (usually professional chefs).  There are plenty of great knife rolls, bags, and cases to choose from.  At bare minimum, make sure you have a blade guard on your knife.

japanese knife sharpening, Japanese Knife Sharpening and Maintenance Guide

japanese knife sharpening, Japanese Knife Sharpening and Maintenance Guide

Long term storage for carbon-steel knives

Here’s a cool tip if you are not planning to use your knife for awhile (i.e. long holiday, business trip, etc.):

  • First make sure the knife is completely dry, then wrap it in a bunch of newspaper.  Newspaper provides good breathability, and the ink can help prevent the blade from rusting.  Store your knife somewhere that is well ventilated with low air-humidity.

Sharpening

A good Japanese kitchen knife will maintain its sharp edge for a very long time, especially when compared to most Western made knives.  Eventually though, like all knives, it will become dull over time and extended usage.   Lack of use over a long period can also cause some carbon steel blades to dull due to corrosion or oxidization of the metal.  Establishing a regular sharpening routine is a good idea.  Professional chefs may sharpen everyday, but at-home chefs can probably get away with sharpening their knives once per month.

Why Sharpen your Knife?

First, a sharp knife cuts betterThis seems like an obvious statement, but a knife that cuts better /cleaner means quicker, and more enjoyable prep with less wasted effort.  Cleaner cuts also helps protect your ingredients.

Using a blunt knife can damage your ingredients, especially more delicate herbs, vegetables, and fruits (e.g. tomatoes!).  Cleanly cut ingredients will preserve their color and flavor longer, as they sustain less bruising / cell damage around the cut area.

japanese knife sharpening, Japanese Knife Sharpening and Maintenance Guide

In Japanese cooking, using a sharp blade is especially important.  For many traditional dishes, the appearance is equally as important as taste, and preparation requires intricate, finely cut ingredients.  For example, when preparing sushi / sashimi, using a blunt knife will not only ruin the beautiful appearance of the raw fish, but also the texture and taste.  

Second, a sharp knife is safer.

A dull knife can slip off your ingredients when cutting, as it is not sharp enough to penetrate the surface/skin.  This means the blade can slide into your other hand or fingers.  A dull knife will also cause you to use more force when cutting, which can further result in accidents, and bloody fingers.

Sharpness Test

Is your knife sharp enough? 

A simple paper test is a good indicator of whether your knife needs to be sharpened or not.

Simply take a standard piece of printer paper, hold it up, and slice through it with your knife.  If you can easily make clean slices through the paper, then your knife is sharp!  See the video below for an example. (Via nozakitoru123 on Youtube. He’s not using a kitchen knife, but same rule applies):

Another simple test is to cut a sponge or tomato.  If you can easily, and cleanly slice through a tomato without using your off-hand to hold it, then your knife is sharp enough! See video below for an example (via Harry Kaufman on Youtube).

 

About Honing Rods

As a general rule, never use honing rods to sharpen your Japanese kitchen knife.  This has been mentioned by many chefs and knife experts much smarter than myself.

Quick fact:
Most honing rods don’t actually sharpen the blade.  They realign or straighten the knife’s edge after it has become bent/deformed from repeated use.  They are used frequently with softer German-steel knives, but are not recommended to use with Japanese knives. 

So, why not use a honing rod on Japanese knives?  As mentioned earlier, a typical Japanese knife is made with a very hard steel (60 HRC or higher) compared to German steel knives (55~58 HRC).   Softer steel is more suitable for honing, as the edge can easily curl or deform with standard usage, and therefore can also easily be straightened out with a honing rod.

On the other hand, Japanese steel will not curl or deform, and therefore does not require honing.  Using a honing rod also runs the risk of chipping the harder, thinner, more brittle steel.  Therefore, there is no reason at all to use a honing rod with a Japanese knife.  If you feel your knife is getting dull, then it may be time to sharpen using a Japanese whetstone.  See below!

How to sharpen your Japanese knife with a whetstone (i.e. waterstone)

japanese knife sharpening, Japanese Knife Sharpening and Maintenance Guide

Using a whetsone is the only recommended way to sharpen your Japanese knife.  For first timers, the task of sharpening your own knife can be daunting, but the process is actually quite straight forward.  As with everything though, practice makes perfect.

If you are not comfortable trying on your own, you can try to find a local sharpening class.  Many manufacturers also offer sharpening services (for a price), so you can avoid doing it yourself altogether.  But, what’s the fun in that??

Here is a basic guide to sharpen a Western style Japanese knife (i.e. double bevel).  Different knife types require slightly different techniques due to blade shape, bevel angles, etc., but the basic principles are the same.

Knife Sharpening Steps

1. Prepare your equipment – Your knife, a towel, bucket/container of water to soak your whetstone, and appropriate whetstone.

Which whetstone should you use?

Whetstones come in various grit sizes depending on purpose.  Low grit stones (120~400) are for rough sharpening, removing chips, and fixing damaged or extremely dull blades.  Medium grit stones (700-2000) are for normal sharpening.  High grit stones (3000+) are for removing scratches, and finishing/polishing the blade.  For beginners like myself, a low grit stone is probably unnecessary, so a medium/high grit stone combo should be enough to start with.   See this article for more info on whetstones.

2. Prepare your whetstone.  Soak it in water according to the supplier’s instructions, usually around 10-20 minutes. When no more bubbles appear in the water, the stone is ready for use.   Some stones (e.g. ceramic) do not need to be soaked in water, while others just need a spray of water, so please read your manufacturer’s instructions first.