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The Principle of Knife Sharpening

Even the best cutting tools eventually loose their sharpness. This is physics, since every metal is subjet to abrasion when being used, leading to wear and subsequently a rounding of the cutting edge (1). The principle of sharpening is hence based on taking material off the sides of the cutting edge (2), so as to create a new pointed tip (3).

This can be done with a variety of sharpening tools, from simple to complex and from cheap to expensive, with their benefits often being controversially discussed in expert circles. However, those experts are all in agreement that the best sharpening results can be achieved on high-grade whetstones. But this needs a bit of practice.

On this page we not only explain you the basics of sharpening on whetstones, but also share important tips for pros and beginners alike. 

rounded and worn cutting edge sharpening to pointed tip removing of material from side

Our PRO Whetstone Set

For our PRO Whetstone Set we have chosen the best materials, so that in sharpening performance, quality and durability they are on the same level than high-grade Japanese whetstones.


The different set components have been selected with the objective of sharpening cutting tools on a professional level to the highest sharpness. At the same time, the superior cutting performance of our whetstones makes it much easier for beginners to achieve good results than with lower grade products.


Our sharpening set can be used for the sharpening of all cutting tools made of metal with a straight and non-serrated edge:

  • all kind of kitchen knives, pocket knives, hunting and outdoor knives

  • straight razors and scissor

  • woodworking and carving tools

  • DIY tools, precision and gardening tools

  • axes, chisels, planes, sickles, adzes

  • machete and swords

The set consists of the following parts:

  • Whetstone #400 grit – for fast abrasion speed in case of damaged or severely rounded edges

  • Whetstone #1000 grit - for sharpening of moderately rounded edges

  • Whetstone #6000 grit - for edge polishing 

  • Leather stropping block with flesh and grain side - for mirror polishing of the edge, stropping the edge after whetstone sharpening, and for regular stropping to maintain the sharpness 

  • Cleaning / dressing stone - for cleaning, repairing or levelling of the whetstones 

  • Angle guide - for holding a steady angle during sharpening

  • Sharpening base and non-slip frame - as a holder for the whetstones and the stropping block while sharpening, and for storage of sharpening accessories

Instructions before, during and after sharpening

Richtig Schärfen
  • Although the stones would be ready to use after a short drizzle of water, we recommend soaking them in water for about 5-10 minutes prior to sharpening. Leaving the stones in the water for longer periods of time must be avoided, as the binder that holds the stone together would otherwise start to dissolve and the stones would get soft or even start to disintegrate.

  • Don’t subject the stones to direct sunlight for longer periods of time or dry them with a hair drier, as this may lead to cracks in the stones.

  • During sharpening, material will be abraded from the stones, leading to stains or scars on the stone. This is normal. 

  • After sharpening on a coarser grit, please carefully clean the blade prior to sharpening on a finer grit, so that the finer stones won’t be contaminated with coarse grains.

  • Only clean the stones with the cleaning stone included in the set or with special lapping stones. Don’t clean or flatten it with sandpaper or other abrasives, as this may clog the stone and scratch the blades when sharpening. 

  • Avoid contact of the leather stropping block with water. When putting the block on the silicone non-slip frame with or without the sharpening base, make sure that both the base and the silicone frame have been properly cleaned and dried.

  • When stropping, always pull the blades across the stropping block and never push it into the leather!

  • When using the angle guide, make sure that both the blade and the guide have been properly cleaned and no sharpening residues are inside of the guide, since they could scratch the blade. To prevent scratches, it’s highly recommended to protect the blade with tape in the area where the guide will be placed.

  • After use, please rinse the stones, sharpening base and silicone frame with warm water and dry afterwards.  

  • Store the set in a dry place. 

Sharpening on the Whetstones

The PRO Whetstone Set can produce a mirror polished edge with a hair-splitting sharpness. This is how it’s done:

drawing soaking of whetstone in water 5 minutes

Soak the stone for about 5 minutes in warm water before use.

Put the silicone frame on the sharpening base and put the stone on the frame, with the glass side down. When sharpening a blade for the first time start with the coarsest grit (#400).

drawing sharpening angle of blade 10 - 15 degrees

Find the desired sharpening angle: about 15° per side with Western knives and 10° per side for Japanese knives. It’s important to keep this angle as steady as possible during sharpening. Holding a steady angle is the secret behind a good sharpening result.

drawing sharpening knife blade by moving blade back and forth in 45 degree angle

Hold the blade in a 45° angle to the stone and move the blade back and forth across the stone, applying light pressure.

drawing sharpening back side of blade at heel in 90 degree angle

When flipping the blade to the other side, the angle will become close to 90° when sharpening near the heel.

drawing knife blade sharpening in 3 zones tip middle heel

Depending on the length of the blade, sharpen in 2–3 sections: tip first, then the middle section and finally the heel area.

drawing sharpening burr on the opposite side

Once a burr can be felt on the entire length of the edge, flip the blade and sharpen on the other side, until the burr can also be felt there.

If an edge is badly worn or when reprofiling an edge, it may take a while until a burr has been formed, even on the coarsest grit. In such cases it‘s recommended to regularly change sides even if a burr has not yet been formed. This is necessary to maintain the symmetry of the edge.


Next, clean the blade well and move to a finer grit. Repeat the steps above until a burr has been raised on both sides of the blade. Then move to the next finer grit. 


After you have been able to raise a burr on the finest grit, move to stropping. Please note that the finer the grit, the less pronounced the burr will be.


Stropping is the final step in sharpening. It refines the edge and removes the burr.

  • When stropping, the blade is pulled (don‘t push!) with the entire length of the edge across the finest grit whetstone with one stroke, changing sides and loosening pressure with each stroke.

  • After stropping on the finest stone, change to the leather stropping block and repeat the above steps. It’s essential that the blade has been cleaned and dried well, to avoid moistening the leather or contaminating it with grains from the whetstone.

  • For best sharpening results, it’s recommended to strop on the flesh side of the leather until a mirror finish has been produced. Afterwards finish by stropping on the smooth grain side of the leather.  

IMPORTANT:  When stropping, keep the same angle than the one used during sharpening.

Grafik zeigt Abziehbewegung Rückseite Messer vom hinteren Ende der Klinge in einem Zug zur Spitze hin ziehen
Grafik zeigt Abziehbewegung Vorderseite Messer von Spitze aus Klinge über Leder nach vorne schieben

Cleaning / Dressing Stone

All whetstones are subject to wear. During sharpening, metal particles can clog the stone and reduce its cutting ability. After heavy use, the stone will dish. Unintended slipping during sharpening can create deeper cuts or scratches on the stones. All of the above can be repaired with the cleaning stone in the sharpening kit.

If the surface of the whetstone is very dirty or the cutting ability feels reduced, rub with the cleaning stone on the surface until all scars have been removed. Afterwards rinse both cleaning stone and whetstone well.

If the stone has dished, work more and longer on those parts that are worn less, until the entire surface has been leveled.

Angle Guide

Holding a steady angle is one of the major challenges in whetstone sharpening, especially for beginners, but is essential for a good sharpening result. Our angle guide will assure that a steady angle is kept, thus making it a lot easier to obtain a good result.

  • Clean the angle guide well before use. 

  • Slide the angle guide on to the blade, starting from the tip and moving it to the middle.

  • To prevent the blade from being scratched by the angle guide, it’s highly recommened to protect the entire upper area of the blade with a tape. 

  • Then sharpen according to the instructions in this manual. 

Once you are getting used to the sharpening strokes, try sharpening without the angle guide.

drawing sharpening back side of blade with angle guide
sharpening front side of blade on whetstone with angle guide

How to keep your blades sharp permanently

When the sharpness of a newly sharpened blade begins to fade, this usually is not due to a rounded edge, but a bent one. Here the very thin tip of the blade is slightly misaligned, so that the tip hits the cutting medium no longer in a perfect 90° angle, which is felt as reduced sharpness.


A bent or misaligned edge can easily be straightened on the stropping block. Here, the blade needs to be dragged across the smooth grain side of the stropping block with medium pressure, with about 5–10 strokes on each side before changing to the other side. Reduce the number of strokes per side and the pressure, so that at the end you strop with light pressure and alternating strokes. 


IMPORTANT:  Keep the angle constant and never push the blade into the leather!


If the sharpness can’t be restored by stropping, the edge has been rounded and needs to be sharpened on the whetstones. If the blade is only slightly rounded, a few strokes on the finest whetstone, followed by stropping on stone and block, will be enough to restore the edge. The more rounded an edge, the more material needs to be taken off the edge and the coarser a grit is needed.

drawing realigning bent edge by stropping

How often do I need to sharpen?

A rule of thumb for a household with 4–5 kitchen knives made from good steel, and daily cooking:


  • Stropping on the stropping block every 2–4 weeks

  • Sharpening on a fine grit whetstone every 8–12 weeks and stropping thereafter

  • Sharpening on a medium or coarse grit whetstone every 6–9 months and stropping thereafter

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