What is a Whetstone & How is it Made?

If you’re into hunting knives, pocket knives, or you spend time in the kitchen like a pro chef, you probably know there’s no better way to keep a blade sharp than with a whetstone. That said, not everyone fully understands what a whetstone is — or how to pick the right one. And yes, the difference between synthetic and natural stones actually makes a big impact.

Japan has been perfecting the art of sharpening for centuries — which makes sense when you think about their legendary sword-making history. Interestingly, the term “whetstone” has nothing to do with water, even though many people assume it does. “Whet” simply means “to sharpen.”

These days, whetstones come in a wide range of grit levels — from coarse to ultra-fine. If you’re working with high-quality steel or precision Japanese knives, maintaining the edge takes a little care. Waterstones give you excellent control, much more than most sharpening tools out there.

Different stones do different jobs: coarser grits are great for fixing dull or damaged blades, while finer stones are perfect for polishing and finishing touches. Knowing the basics of how they work makes it a lot easier to choose the right whetstone for your knives.

Understanding the Whetstone: A Timeless Tool for Sharpening

A whetstone is a simple but powerful tool — usually a rectangular stone — used to sharpen knives, tools, and other blades. The word “whet” actually means to sharpen, not wet, even though many whetstones do use water during the sharpening process.

These sharpening stones have been available for centuries now. A few of the earliest recorded uses go way back to 79 AD. In fact, diverse parts of the world have created their own unique versions; from Japan and Arkansas to Belgium and England; frequently utilizing natural materials such as fine sedimentary shale or novaculite.

In Japan, the use of whetstones goes back even further, to the Jomon period (around 13,000 BCE). With an abundance of natural sharpening stones, Japan became a hub for crafting and maintaining some of the world’s sharpest blades — including the legendary samurai swords.

Today, whetstones are still a must-have for professional chefs, home cooks, hunters, and anyone who appreciates a well-maintained knife. Most modern stones fall into two categories: natural or synthetic. Both types do a great job of sharpening, polishing, and even repairing blade edges — but they each have their own pros and cons. Choosing the right one depends on your blade type, skill level, and how much time you’re willing to invest in proper maintenance.

Types of Whetstones

Natural vs. Synthetic Whetstones

There are two main types of whetstones: synthetic and natural.

Natural whetstones are mined from the earth in places like Japan, Arkansas (USA), Germany, Belgium, and Turkey. These stones are formed from dense, fine-grained rocks that naturally have abrasive qualities. Japanese natural stones — often called JNATS — are especially famous for producing ultra-sharp, polished edges. They’re typically quarried near Kyoto and carefully cut using diamond saws.

That said, natural stones aren’t always consistent. Since they’re formed by nature, no two are exactly alike. The grit and hardness can vary from stone to stone, which might not be ideal if you're looking for predictable results.

On the other hand, synthetic whetstones are man-made. They’re made by bonding abrasive particles like silicon carbide or aluminum oxide into a ceramic base. The benefit? Manufacturers can control the grit level and performance more precisely. These stones tend to offer reliable, even sharpening — but they can wear unevenly over time and may need to be flattened after heavy use.

Water Stones vs. Oil Stones

When it comes to lubricants, water stones and oil stones take different approaches.

Water stones need to be soaked in water before use — usually until you stop seeing bubbles rise to the surface. The water forms a slick layer that helps reduce friction and carry away metal particles while sharpening. As you use the stone, tiny particles wear off to create a fresh, abrasive surface that keeps working efficiently.

Oil stones, on the other hand, use mineral oil instead of water. These stones are often harder and cut more slowly, but they’re very durable. Some people prefer oil stones for certain types of blades or for more controlled sharpening sessions.

Diamond Stones

In the sharpening world, diamond stones are really the heavy-hitters. They are created by bonding a flat metal plate and industrial-grade diamonds together. Diamonds stones do not wear out that easily since diamonds are one of the hardest materials available on earth. These stones also never essential soaking. They provide aggressive, fast sharpening and are ideal for those who desire a high-performance, low-maintenance option.

How Is a Whetstone Made?

Natural Whetstones

Natural whetstones are formed over thousands (sometimes millions) of years within the earth’s rock layers. They’re carefully mined from select regions known for producing high-quality sharpening stone — like Japan, Arkansas, Belgium, and Germany.

Manufacturers look for stone types rich in quartz and other fine abrasives with just the right level of hardness. But here’s the catch: not every deposit is usable. Good-quality natural stone is rare and becoming harder to find, which makes these stones more expensive and sought after by professionals and collectors.

The production process is fairly simple. Once the stone is quarried, it’s cut into manageable blocks, shaped, and smoothed into usable whetstones — all without any added chemicals. While natural stones offer unique sharpening characteristics, one downside is that no two are exactly the same. That means grit levels and performance can vary.

Synthetic Whetstones

Synthetic whetstones are a modern solution to the limited supply of natural options. These stones are made using abrasive compounds like aluminum oxide (also known as electrocorundum) or silicon carbide (also called carborundum).

Manufacturers mix these abrasive particles with a bonding material — usually ceramic — and then mold them into uniform blocks. This process allows for total control over the grit size, consistency, and overall hardness of the stone.

The result? A wide range of whetstones that can be made for specific sharpening needs, from coarse grinding to fine polishing. Synthetic stones are often more affordable, easier to find, and more predictable in terms of performance. Plus, they can last you for a long time if taken care of properly.

Diamond Stones

These stones are in a different league of their own. These tools feature a thin metal plate coated with industrial-grade diamond grit — one of the hardest substances on earth. Because of this, diamond stones don’t wear down easily and don’t require soaking like traditional stones.

They’re also very efficient. Just a quick spray of water is enough to get started, and they can sharpen even the toughest blades with minimal effort. However, diamond stones remove metal aggressively, so it’s best to use them for coarse sharpening or reshaping dull blades. Afterward, many users switch to a finer whetstone to finish the edge more gently.

Grit Levels & Their Uses

If you're getting into sharpening, one of the first things to understand is grit level — basically, how rough or smooth the whetstone’s surface is. In general, lower numbers mean coarser stones (used for heavy-duty sharpening), while higher numbers give you a finer, more polished edge.

Here is a simple breakdown to assist you in selecting the correct grit for the blade:

Coarse Grit (200–600)

These stones are used when your blade is in rough shape.

200–400 grit: Ideal for fixing chipped, damaged, or very dull knives. They reshape the edge by removing the metal quickly.

600 grit: Though it is still on the coarse side, but a little more refined; amazing for touching up your kitchen knives with slight edge defects.

Use coarse grit sparingly — it's aggressive and should only be used when necessary.

Medium Grit (800–1500)

This is your go-to range for regular maintenance.

1000 grit is often the "universal" starting point. It offers a balance between sharpening power and control.

Most manufacturers recommend a 1000-grit stone for everyday sharpening tasks — it gives great results without taking off too much metal.

If you only purchase one whetstone, this grit range is typically the best place to begin.

Fine Grit (3000–8000)

Once the knife is sharp, the stones assist in polishing the edge and refining the finish.

3000 to 5000 grit: These create a noticeably sharper, smoother edge — especially helpful for slicing meats or vegetables with ease.

6000 grit: A popular option among chefs for achieving that clean, professional finish.

8000 grit: Adds a mirror-like polish to the edge — ideal for premium blades or those who want the sharpest cut possible.

Ultra-Fine & Specialty Grits (10000+)

This is where things get niche — and pricey.

Stones rated 10,000 to 12,000 grit are mostly used by collectors, professional sharpeners, or sword enthusiasts.

They’re not commonly found in stores and are rarely needed for general kitchen use.

That said, they can deliver an unbelievably smooth finish for those who want perfection.

Pro Tip: Don’t rely on just one stone. Using a combination of coarse, medium, and fine grits gives you the best sharpening results — from fixing damage to creating a razor-sharp edge.

Why Choose Whetstones for Knife Sharpening?

When it comes to sharpening knives properly, whetstones are hard to beat. Unlike electric sharpeners, which can grind away too much metal or damage the steel’s structure, whetstones give you total control over how much you sharpen and where.

That’s exactly why both professional chefs and home cooks prefer them — they allow for precision, consistency, and care.

Wider whetstones are especially user-friendly. They provide more surface area to work with, letting you control the angle, pressure, and movement of the blade. As you glide the knife along the stone, a thin layer of slurry (a mix of water and abrasive particles) forms, helping to sharpen the blade evenly and efficiently.

A few tips go a long way:

• Use light, consistent pressure
• Slide the knife at the correct angle
• Reapply water as needed to maintain lubrication

This process gently removes metal, maintaining your knife’s shape and prolonging its lifespan.

Beyond the technical benefits, whetstones also help you develop proper sharpening skills. Once you learn the technique, you’ll get sharper edges and better results than most automated tools can deliver — without sacrificing your blade.

And with good care, whetstones can last you for a long time, making them a cost-effective and smart investment for anybody who values well-maintained knives.

Necessary Tips for Using a Whetstone

Sharpening the knife using a whetstone is easy once you comprehend the steps. With a little practice, anybody can master the procedure. Here are a few useful tips to get the great results:

• Submerge oak water stones correctly
  
• Maintain a consistent angle
  
• Keep the surface wet
  
• Use steady, light strokes
  
• Switch grits as needed
  
• Sharpen safely
  
• Even out both sides
  

Whetstones frequently have instructions, but hands-on practice is what really builds skill and confidence. Stick to these tips, and you’ll be sharpening like a pro in no time.

Final Thoughts

Whetstones represent one of the simplest and most effective ways to maintain sharp edges. It’s no surprise that Japan—rich in natural stone resources—perfected the art of sharpening, guided by the cultural philosophy that “simple is best.”

Whether you choose a natural or synthetic option, a quality whetstone remains essential for keeping your kitchen knives in peak condition. Once you get the hang of it, you’ll be surprised at how easy and satisfying it is to restore a razor-sharp edge with your own hands.