Open almost any Japanese sword maintenance guide and you will find uchiko presented as a standard step in blade care — tap the ball along the blade, wipe clean, apply oil. The procedure is described as routine and universal. For antique nihonto, this is broadly correct. But there is a perspective on uchiko that these guides almost never include: the perspective of the living swordsmiths who make modern fine art blades. Tozando recently confirmed directly with Kubo Yoshihiro, President of the All Japan Swordsmith Association, and Tsubouchi Tetsuya, Secretary General and former swordsmith Suketada, that most contemporary swordsmiths advise against using uchiko on newly forged and modern fine art swords — while affirming that uchiko use on antique blades is entirely appropriate. This article explains the reasoning behind both positions.
What Uchiko Actually Is — The Polishing Dust Origin
The name uchiko (打粉) means "struck powder" or "tapped powder" — a reference to the action of tapping the silk-wrapped ball against the blade to release the fine particles inside. Understanding what those particles actually are is essential to understanding the debate around uchiko use.
Authentic uchiko is the powder of uchigumori (内曇砥) — the finest natural whetstone used in the final stages of Japanese sword polishing. Uchigumori is a soft, fine-grained natural stone that produces a slightly grey powder with rounded particles. When this powder is correctly prepared and applied, the rounded particle shape means it is less likely to leave scratches (known as hike) on the blade surface. It is, by nature, the gentlest abrasive in the togishi's toolkit — the last stone used before the blade is considered finished.
However, genuine uchigumori is extremely expensive and increasingly scarce. As a result, many commercially available uchiko products contain additives or substitutes — including ox-horn powder or gofun (胡粉, calcium carbonate produced by firing shells). These additives tend to clump in humid conditions and can cause fine scratches on the blade surface. Kubo Yoshihiro and Tsubouchi Tetsuya confirmed to Tozando that low-quality uchiko with such additives is not recommended by serious modern collectors or togishi — and that this quality issue is part of the context behind swordsmiths' reservations about uchiko on newly forged blades.
The abrasive action of uchiko — even high-quality uchiko — is real, and over repeated applications it accumulates. Tsubouchi Tetsuya, Secretary General of the All Japan Swordsmith Association, confirmed this directly to Tozando: uchiko has the potential to scratch the blade surface. The risk depends on the quality of the uchiko and the type of polish finish on the blade.
Two Categories, Two Different Answers
The uchiko question does not have a single universal answer. It has two answers, depending on which category of blade you are maintaining — and confusing the two is the source of most of the debate in collector communities.
A newly forged sword arrives in a specific condition: the exact state in which the togishi left it, with every element of the ji character and hamon clarity carefully realised. This is the ubu state — original and unaltered.
The swordsmith's wish is for the first owner to experience and preserve this state. Uchiko, as polishing dust, removes surface material with each application — gradually altering the very finish the togishi created. A soft cloth removes old oil just as effectively, with no abrasive action whatsoever.
This is the majority position among contemporary swordsmiths. A minority do use uchiko on their own blades — sword-making communities, like all communities of practice, contain a range of views. But the consensus view of the All Japan Swordsmith Association's leadership is clear: for modern fine art swords, a soft cloth is the recommended approach.
For antique blades, the All Japan Swordsmith Association leadership confirmed to Tozando: uchiko use presents no problem. The traditional maintenance practice — uchiko to lift old oil and surface particles, followed by fresh oil application — is the correct approach for antique nihonto and has been used for generations.
Antique blades have typically been through multiple polish cycles over their lifetimes. The surface character of a well-maintained antique reflects decades or centuries of appropriate care, including regular uchiko use. The tradition of katana ga sodatsu (刀が育つ, "the sword grows") — the idea that correct maintenance improves an antique blade's surface over time — is well-founded for this category.
Use uchiko correctly: tap the ball against the blade rather than rubbing, work from habaki to kissaki, and wipe clean with nuguigami before applying fresh oil. One practical note: the quality of the uchiko matters. High-quality uchiko made from genuine uchigumori powder with rounded particles is far less likely to cause surface scratches than cheaper products containing ox-horn powder or gofun additives. If possible, source uchiko from a reputable specialist Japanese sword supplier rather than general martial arts retailers.
has something no subsequent owner can have:
the blade exactly as the smith and togishi left it.
A soft cloth preserves that.
Uchiko changes it, application by application."
The Ubu State — Why the First Owner's Experience Is Irreplaceable
The swordsmiths' advice about uchiko connects to something larger about what a newly forged sword is and what it offers the first owner. When you acquire a blade directly from a living smith — or through a dealer like Tozando who works directly with living smiths — you receive it in the ubu (生ぶ) state: original, unaltered, precisely as it left the forge and the togishi's workshop.
This state is available only to the first owner. Every subsequent owner will inherit a blade that has been through some degree of handling, maintenance, and the passage of time. The first owner alone experiences the sword at the exact moment the makers considered it complete.
Preserving the ubu state — keeping the polish as close as possible to what the togishi created — is the practical expression of respecting what the blade is. A soft cloth, used carefully every few months with fresh sword oil, achieves this. Uchiko achieves the same oil removal but at the cost of gradually modifying the very surface the togishi spent weeks realising. For the first owner of a newly forged blade, the swordsmiths' preference for the soft cloth approach is not merely a technical recommendation — it is an invitation to honour what they made.
Practical Maintenance — The Correct Approach for Each Category
For newly forged and modern fine art swords — the soft cloth method:
Using clean nuguigami (Japanese maintenance tissue) or a soft, lint-free cloth, wipe the blade gently from habaki to kissaki, using a fresh area of material for each pass. This removes old oil and surface particles without any abrasive action. Apply 2–3 drops of sword oil to a clean applicator and wipe a thin, even coat across both sides. A barely visible sheen is the correct amount — excess oil pools in the habaki and saya. Repeat every 3 months under normal storage conditions.
For antique nihonto — the traditional uchiko method:
Tap the uchiko ball lightly along the blade from habaki to kissaki — do not rub or drag it. The tapping action releases a small amount of powder onto the surface. Wipe clean with nuguigami, removing both the powder and the old oil it has lifted. Apply fresh sword oil thinly. The critical point is tap, not rub: rubbing the uchiko ball increases the abrasive force and risks scratching a polished surface. Used correctly with a tapping motion, uchiko is entirely appropriate for antique blades.
Quick Reference — Which Approach for Which Blade
for antique and modern blades alike
Tozando's maintenance kit includes authentic nuguigami, high-quality sword oil, premium uchiko, and mekugi-nuki. Every blade purchased from Tozando comes with specific advice on appropriate maintenance for that piece. Contact our specialists with any maintenance question about a blade in your care.
In Closing — Two Traditions, One Principle
The uchiko debate is, at its core, a debate about what the maintenance practice is for. For antique nihonto, uchiko is part of a tradition of care that has served generations of blades well — the correct tool for the context, used as generations of collectors and dealers have used it. The All Japan Swordsmith Association confirms this without reservation.
For newly forged and modern fine art swords, the swordsmiths who made the blades offer a different perspective: the surface they created is the blade's original state, and preserving it as closely as possible is the appropriate response to what has been entrusted to the first owner. A soft cloth achieves the necessary oil removal without the abrasive action of uchiko.
Not every contemporary swordsmith holds the same view — individual practice varies within the community, as it does in any craft tradition. But the majority position, as confirmed by the leadership of Japan's national swordsmith organisation, is clear: for newly forged and modern fine art blades, the soft cloth is the recommended approach. For antiques, uchiko remains entirely appropriate.
The principle underlying both positions is the same: maintain the blade in a way that respects what it is. For an antique, that means the tradition of uchiko care its previous owners have practised. For a newly forged sword, it means preserving the ubu state that only the first owner can fully experience — and that no subsequent maintenance can restore once it has been altered.
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