Knife Sharpening 101 – How to Sharpen a Knife

Originally published in 2014, this guide was updated in September 2026 with expanded information on knife steels, edge grinds, sharpening stones, sharpening techniques and edge maintenance.

Knife sharpening is an important skill in the kitchen, on the fishing boat and in the outdoors. A sharp knife requires less force to make a cut, giving you better control and reducing the chance of the blade binding or slipping. When processing fish, a properly sharpened knife also produces cleaner cuts and helps you get the most meat from each fillet. This guide covers knife edges, sharpening techniques and several types of sharpening tools, along with selected videos that demonstrate the techniques in more detail.

To put together this article, I reviewed a number of knife-sharpening videos on YouTube and selected several that provide clear, practical explanations. You can work through the series or return to individual videos as you learn each technique. Several of the videos feature Richard Blaine, who provides detailed explanations of the sharpening process.

Sharp knives are especially important when cleaning fish. Halibut, lingcod and salmon each present different challenges when filleting and processing, from heavy bones and thick skin to making clean cuts without wasting meat. For more information on catching and handling these species, see the FishinBC.COM Complete Guide to Halibut Fishing, Complete Guide to Lingcod Fishing and Complete Guide to Salmon Fishing.

Knife Materials and Grind Types

The steel, shape and construction of a knife all affect how it performs and how it should be sharpened. For a fishing knife, the hardest or most expensive steel is not necessarily the best choice. Flexibility, toughness, corrosion resistance and the ability to quickly restore an edge can be just as important, particularly when a knife is being used around saltwater and fish bones.

Understanding Knife Steels

The type of steel used in a knife affects how sharp an edge it can take, how long it stays sharp, how easily it can be sharpened and how well it resists corrosion. These properties involve trade-offs. Harder steels can generally hold a fine edge longer, while somewhat softer and tougher steels can be easier to sharpen and more tolerant of the bending and twisting that can occur when filleting fish.

Many familiar fishing knives from manufacturers such as Rapala, Dexter, Victorinox and BUBBA use stainless steels selected for practical working conditions. The exact steel varies between manufacturers and models, but corrosion resistance, toughness and ease of maintenance are important characteristics for a fillet knife. A knife that needs to be touched up more frequently is not necessarily a poor-quality knife. Being able to quickly restore the edge can be an advantage when processing a number of fish.

At the other end of the spectrum, high-quality Japanese kitchen and sushi knives can use very hard carbon, stainless or powdered steels capable of taking and retaining an extremely fine edge. These knives can produce remarkably clean cuts, but some require more care. Carbon steel requires additional attention to prevent corrosion, while very hard, thin edges can be less tolerant of twisting, impacts or contact with hard bone.

There are many knife steels between these examples, and the steel itself is only part of what determines how a knife performs. Heat treatment, blade thickness, flexibility, edge geometry and the quality of manufacture are also important. For sharpening purposes, the important point is to understand the knife you are working with rather than assuming every blade should be sharpened in exactly the same way.

Knife Edge Grinds

The grind describes how the sides of the blade are shaped as they approach the cutting edge. Many fishing and Western-style knives have a symmetrical edge, with the bevel sharpened approximately 50/50 on each side. Some Japanese knives use an asymmetrical edge, where more of the bevel is formed on one side of the blade than the other.

Before sharpening a knife, it is useful to identify its existing grind and edge angle. The goal is generally to maintain the edge the knife was designed to use rather than unintentionally changing its shape while sharpening.

This video explains several knife materials and edge grinds and how they affect sharpening.

Knife Sharpening How To Use A Sharpening Steel Part 2

Fillet Knife Handles

The handle is another important consideration when choosing a fillet knife. Fishing knives are frequently used with wet or slippery hands, so many purpose-built fillet knives use textured or rubberized handles designed to provide a secure grip. A finger guard or similar handle design can also help reduce the chance of your hand sliding forward toward the blade.

For a knife used to process fish, the handle should also be easy to clean and made from materials suitable for food-contact use. Many commercial and fishing knives use molded synthetic handles that do not readily absorb water and can be thoroughly washed after processing fish.

On a fishing boat, these practical features can be more important than appearance. I look for a handle that provides a secure grip when my hands are wet or covered in fish slime, is comfortable enough to use while processing several fish, and can be easily cleaned when the job is finished.

How to Sharpen a Knife

There are several ways to sharpen a knife, but the basic objective is the same: remove a small amount of material from the cutting edge while maintaining the correct angle until a sharp, consistent edge is formed. One of the most important skills is learning to hold that angle consistently as the blade moves across the sharpening surface.

You do not necessarily need to reproduce an exact angle measured in degrees every time you sharpen a knife. For a knife that already has an appropriate edge, a practical approach is to identify the existing bevel and follow it. Consistency is more important than repeatedly changing the angle as you work along the blade.

As you sharpen one side of the knife, a very small burr can form along the opposite side of the cutting edge. Feeling for this burr is one way to confirm that you have worked the edge far enough for the bevel to reach the cutting edge. After working both sides, progressively lighter strokes can help refine the edge and remove the remaining burr.

Knife Sharpening Strokes

The first video demonstrates one method of sharpening a knife on a stone. One point I found particularly useful is the acknowledgement that there are many ways to sharpen a knife. The exact stroke can vary, but maintaining the blade angle and working the entire cutting edge consistently are important.

I also found the explanation of how to find the existing sharpening angle useful. The video demonstrates placing the blade on the stone and gradually raising the angle until the edge begins to “stick” to the sharpening surface. This provides a practical way to find the existing grind angle before beginning to sharpen.

Knife Sharpening: How To Sharpen A Knife: The Western Stroke

Japanese Waterstones

Japanese waterstones are another traditional approach to sharpening knives. They are available in different grits, allowing a coarser stone to repair or establish an edge and progressively finer stones to refine and polish it. Depending on the type of waterstone, it may need to be soaked before use or simply wetted on the surface.

Waterstones gradually wear as a knife is sharpened. This helps expose fresh abrasive material, but it also means the surface can eventually become uneven and require flattening. We will look at maintaining a flat sharpening stone in the next section.

The following video demonstrates another sharpening method using Japanese waterstones. As with the previous technique, the important lesson is not that there is only one correct sharpening stroke, but that the existing edge angle should be maintained consistently while working along the blade.

Knife Sharpening: How To Sharpen A Knife On A Wet Stone: How To Maintain Japanese Waterstones

Sharpening Stones

Sharpening stones are available in a range of materials and grits. Common examples include natural stones such as Arkansas stones, synthetic waterstones and ceramic stones, as well as diamond sharpening plates. Each works somewhat differently, but they all provide an abrasive surface that removes a controlled amount of steel from the cutting edge.

Grit is an important consideration when choosing a sharpening stone. Coarser abrasives remove material more quickly and can be useful for repairing or reshaping a dull or damaged edge. Finer abrasives remove less material and are used to refine the edge. For routine sharpening, there is generally no reason to start with a very coarse abrasive if the knife already has a reasonably good edge.

Diamond Sharpening Stones

Diamond sharpening stones use industrial diamonds bonded to a flat surface. Because diamond is a very hard abrasive, these stones can remove steel efficiently without requiring much pressure. They are also useful with harder knife steels that can take considerably longer to sharpen on some traditional stones.

One feature I like about diamond stones is their convenience. Unlike waterstones that may require soaking and eventually need to be flattened, a diamond plate can generally be used with very little preparation and maintains a flat sharpening surface. The abrasive surface can still wear with use, so I would not consider a diamond stone wear-free. As with any sharpening tool, light, controlled strokes are preferable to forcing the blade against the abrasive.

In the following video, Richard Blaine discusses several sharpening tools and demonstrates diamond stones manufactured by DMT.

Knife Sharpening: The Gear I Use To Sharpen My Knives

How to Maintain a Waterstone

Waterstones gradually wear as knives are sharpened on them. Over time, repeated sharpening can create a hollow or uneven area in the surface, particularly where the knife most frequently contacts the stone. A stone that is no longer flat can make it more difficult to maintain a consistent edge angle while sharpening.

Flattening restores the stone to an even working surface. How often this is necessary depends on the stone and how frequently it is used, so it is useful to periodically check the surface rather than waiting until the wear becomes severe.

The following video demonstrates how to flatten and maintain a waterstone so it continues to provide an even surface for sharpening.

Knife Sharppening How To Clean And Maintain Your Knife Sharpening Gear

Other Knife Sharpening Tools

Pull-Through Sharpeners

Pull-through sharpeners are a convenient option when you need to quickly touch up a knife and do not have the time or space to set up a sharpening stone. I find them particularly useful on the boat, where a rocking deck can make sharpening a knife on a stone awkward or unsafe. A few controlled passes through a pull-through sharpener can quickly improve an edge and get the knife back to work.

The trade-off is that some pull-through sharpeners, particularly those using carbide cutters, can remove steel quite aggressively. I have had a pull-through sharpener dig into the cutting edge of a knife and leave a small chip. I cannot say exactly what caused it, although excessive pressure may have contributed.

This experience taught me to use a light, steady touch and let the sharpener do the work rather than forcing the blade through it. The knife and sharpener also need to be compatible: a fixed-angle pull-through sharpener may not match the existing grind, and very hard, thin edges can be less tolerant of aggressive sharpening.

For those reasons, I consider a pull-through sharpener a convenient tool for quick touch-ups on an appropriate working knife rather than a replacement for carefully sharpening a knife on a stone. I would be particularly cautious about using an aggressive carbide pull-through sharpener on a high-quality Japanese knife or another knife with a very hard, thin edge.

Sharpening Steels

The term “sharpening steel” can be a little confusing because not every steel works in the same way. A traditional smooth or finely grooved honing steel is primarily used to maintain an existing cutting edge rather than create a new one. Regular use can help keep a working knife performing well between more complete sharpenings.

Other sharpening rods are abrasive. Diamond-coated rods and some ceramic rods can remove a small amount of metal from the blade, so they can actually sharpen the edge rather than simply maintain it. This distinction is useful when deciding whether a knife just needs routine edge maintenance or has become dull enough to require more substantial sharpening.

I found this distinction particularly interesting when reviewing the following video. It goes through several types of sharpening steels and explains the difference between maintaining an existing edge and using an abrasive rod that removes material from the knife.

Knife Sharpening How To Use A Sharpening Steel Part 1

Your Turn

There are many ways to sharpen and maintain a knife, and everyone seems to develop their own preferred tools and techniques. I prefer to have my knives properly sharpened before I get to the boat rather than sharpening them while I am fishing. If an edge needs attention during the day, a quick touch-up can usually get the knife back to work. Once your knife is sharp, the FishinBC.COM tutorial How to Fillet Your Salmon or Halibut with Less Waste shows how I use it when processing fish.

What works best for you? If you have a favourite sharpening tool or technique—or a tip for keeping fillet knives sharp while fishing—share your experience in the comments below.