To keep your steel katanas sharp, you need to sharpen them with whetstones. We recommend you consult some video guides before sharpening your katana at home. You can also ask a local blacksmith to do it for you.
Why is sharpening a katana so difficult?
Katanas are notoriously difficult to sharpen. Their intrinsic value and meticulous workmanship require the highest quality tools. The first challenge lies in the curvature of the blade, and in particular the different angles of the tip (Kissaki).
Curved blades are already difficult to sharpen, but the difficulty is increased with the high-quality steel used and the need to maintain the initial bend when sharpening.
Unlike most knives with a diagonal sharpening pattern, katanas require sharpening from opposite angles to achieve the sharpest possible edge. A mistake or excessive sharpening can quickly compromise the blade’s edge.
What tools are required to sharpen a katana?
Sharpening a katana requires specific tools, including various grit water stones. These stones can be expensive, depending on their quality. They must be highly grained and refined, as any imperfection can permanently damage the blade. A 2,000-grit stone, for example, is ideal for recovering a dull, damaged blade, while a 10,000-grit stone with a much finer grit is ideal for refining and sharpening an already sharp blade.
In addition to sharpening stones (whetstones), other tools are also required:
- 1 container with clean water,
- 1 cloth to wipe the blade,
- 1 spray bottle or dropper to keep the stone moist,
- 1 comfortable work surface,
- 1 vice or towel to stabilize the stone,
- 1 toolset to remove the katana handle,
- and paper or foam to test the cutting action.
Once you have all the tools you need, you can then begin the sharpening process.
⚠️ Warning before sharpening a katana yourself
Before you start sharpening your katana, it’s crucial to master a few key points. Firstly, you must use appropriate tools. Secondly, handle your katana with extreme care, as the slightest error can damage the blade and yourself. Finally, remember that sharpening a katana takes time and patience, so don’t rush.
Katanas made of carbon steel (1045, 1060, T10…) can be sharpened using this method without any problems. However, we do not recommend sharpening stainless steel katanas intended solely for cosplay and decoration.
How to sharpen a katana with a whetstone?
Now that you’ve got the basics down, let’s get down to business. There are various ways to sharpen a katana, but using a whetstone remains the most traditional. These detailed steps will guide you through the katana sharpening process, with practical advice at every stage. Follow them carefully to achieve the best results without compromising your blade.
Step 1: Preparing the blade
The first step is to remove the handle (Tsuka), leaving only the blade (Nagasa). To do this, you need to remove the Mekugi, the bamboo pegs that lock the blade tang (Nakago) under the handle. During this operation, protect the blade in its scabbard to avoid any possible incident.
To do this, push the Mekugi sideways from its thinner side to bring it out of its thicker side. If it’s stuck, use a small hammer to tap a rod to pull the Mekugi out.
Once this is done, place your hand on the top of the handle at the Fuchi and push with your thumb and forefinger on the guard. Then gently pull the handle along the Nagako (blade tang under the handle) until it is completely free.
Then remove the Seppa, the guard, and the second Seppa. You can leave the Habaki. At this point, you’ll normally have the katana tang with the Habaki visible and the blade still in its scabbard.
Step 2: Preparing the whetstone
Depending on the condition of your katana, use a single sharpening stone or two, one medium-grained and another fine-grained. Always start with the coarser-grained whetstone.
Soak the whetstone in water. Sharpening stones or water stones have pores for a reason: these micro-holes collect abrasive particles during the sharpening process, preserving the stone’s efficiency.
However, letting the whetstone dry is not recommended, as it could result in an excessively abrasive surface, risking notching or damaging the Nagasa of your katana. Soaking the whetstone in clean water for 15 to 30 minutes will ensure that it remains saturated for longer when sharpening the katana.
Step 3: Clean the katana to remove surface contaminants
Over time, dust, particles, and even oil residues can accumulate on the surface of your katana, unless it is stored under very strict conditions. Before starting the sharpening process, it is essential to remove all these surface contaminants.
While the water stone is soaking, take a cleaning cloth and hold the katana firmly. Gently and carefully wipe the cloth over the Nagasa (blade), taking care to remove all traces of dust, particles, oil, dirt, or other residues.
Step 4: Sharpen the katana
Once your sharpening stone is ready, firmly in place and your katana is clean, you can start sharpening your katana. Using light pressure, place the edge of the blade on the stone and slide the blade back and forth along the stone. Hold the blade at an angle of about 20 degrees to the stone, with the cutting edge in direct contact with it. Use regular, light strokes to sharpen both sides of the blade evenly, e.g. alternating 5 to 10 strokes on each side of the blade. Maintain a constant angle throughout the operation to avoid damaging the cutting edge. Moisten the stone with your water sprayer every 10-20 strokes.
Regularly check to see how it’s progressing, test cutting a sheet of paper by sliding it along the edge. Once you’re satisfied with the result, clean the blade with water and dry it with a clean cloth. Then sharpen the tip of the katana, following the angles in the same way.
Your katana is now sharpened and ready to use! With practice, sharpening your katana will become easier and faster. Be patient, take your time, and always use the right tools to ensure that your katana retains its sharp edge for many years to come. Sharpening a katana requires patience and attention to detail, but the result is well worth the effort. Don’t forget to clean your katana properly, so that it dulls less quickly.
Other ways to sharpen a katana
Some katana enthusiasts prefer to explore alternative approaches to sharpen their blades, often motivated by the speed required by the traditional technique using whetstones. In addition, some may have tools available in their garage or workshop to restore the sharpness of their katana more expeditiously. Although we present these alternative methods, we do not recommend them. They can quickly cause permanent damage to your blade, whilst being less effective.
Abrasive belt
This approach is particularly popular among those under time pressure. By simply switching on the device and positioning the Nagasa on the abrasive belt, an edge can be restored in just a few minutes. However, this method is often strongly discouraged for beginners by many sword experts, especially those who have never sharpened a katana before.
Grinders and similar power tools
Electric power tools offer a faster alternative to abrasive belts for sharpening Japanese swords. Nevertheless, their handling can be a problem for beginners, and there is an increased risk of damaging the katana due to the very rapid abrasive action.
Togishi: Japan’s polishing and sharpening masters
The Togishi, masters in the art of katana sharpening and polishing, hold a central place in Japan’s centuries-old swordsmanship tradition. Dating back to the Kamakura period, between 1192 and 1333, katana sharpening was considered a form of art and spirituality.
Although modern swordsmen polish and sharpen their creations, this task was once exclusively entrusted to the Togishi, specialists in katana polishing. Today, such craftsmen are rare, as mastery of this art requires intensive training and rigorous certification by the Society for the Preservation of Japanese Swordsmanship.
A Togishi certified by the NBTHK must undergo a ten-year apprenticeship, twice as long as the period required to learn the art of swordsmanship. This rarity underlines the importance and preciousness of these experts, as entrusting one’s katana to just anyone would be impossible. It is crucial to distinguish between polishing and sharpening katana. Polishing shapes the katana’s cutting edge (Ha) and gives it its distinctive appearance, while sharpening, which is much quicker, takes just a few hours.