和紙の定義と繊維
Japan’s own industrial standard defines washi, and the definition contains the problem: it says that most washi today is machine-made from chemical pulp. The fibre that gives the material its properties has been measured, and it is not present in every sheet the word is applied to.
The reason is fibre length, and it has been measured. Yamashita, of the Kochi Prefectural Paper Technology Center, gives the figures in Hyomen Kagaku in 2017: kozo fibre runs 6 to 21 mm and averages 9.4; gampi 3 to 5 mm, averaging 3.2; mitsumata 3 to 5 mm, averaging 3.5. Conifer pulp is 2.0 to 3.0 mm and poplar averages 1.5. Widths barely differ — 10 to 30 micrometres for the bast fibres against 22 to 50 for wood — so what changes is the ratio of length to width, and he names that ratio as the major factor behind the bulk and the tensile strength that characterise washi.
Now the definition. JIS describes washi as a general term for paper that developed in Japan, divided into hand-made and machine-made; originally, it says, paper made from bast fibre using neri and the hand-made method — and then adds that at present much of it uses chemical pulp and the machine method. That is the standard saying, in its own words, that the term now covers paper made from neither the fibres above nor the process below. A listing using the word is not misusing it. It is simply not telling you which of the two you are getting.
The process is the other half. Yamashita separates two ways of using the mould: tame-zuki, where the stock is held and the water simply drains, which suits thick papers; and nagashi-zuki, where neri — a viscous liquid extracted from certain plants — is added and the mould is worked back and forth so that the sheet builds under control. Nagashi-zuki is what makes long fibres into a thin sheet rather than a thick one, and he writes that most of the technique developed in Japan. The thin papers the tradition is known for are its products.
The designation people cite follows the process rather than the word. UNESCO’s intangible cultural heritage listing, inscribed in 2014, is titled the craftsmanship of traditional Japanese hand-made paper, and it names three papers: Sekishu-banshi in Shimane, Hon-minoshi in Gifu and Hosokawa-shi in Saitama. It is a listing of specific hand-made traditions in specific places, not a description of everything sold as washi.
What this page does not tell you is how long any of it lasts. The source above measures fibre and describes technique; it does not measure ageing, and the thousand-year figure that circulates with this material is not something this site has a measurement for. Treat the fibre and the method as what is established here, and the longevity claim as a separate question that would need a separate source.
No shop link here. The single question this page says to ask — which fibre, and hand-made or machine — is one that most listings do not answer, and linking a sheet whose fibre is not stated would undo the page in the act of monetising it. If a seller does state the fibre and the method, that is the seller worth reading; if the description stops at the word, the description has told you nothing the standard does not already allow.
Sources The other guides鉄瓶と鉄急須
One boils water and gives you iron. Putting the other on heat cracks its lining for good.
金継ぎと食器
Not urushi against epoxy. Whether the material states food-contact compliance.
鉄瓶の錆
The spots appear in the first week. The makers’ association says do not take them off.
漆と抗菌
A prefectural institute put eleven lacquer films through JIS Z 2801. Most came back undetectable.
土鍋の熱
It conducts heat badly. That is the product — and it is also why it cracks.
鉄瓶と鉄分
The form is settled by a 2003 paper. The amount is not settled by anything.
せいろのカビ
The usual fix starts by soaking it. A seiro maker calls soaking strictly forbidden.
土鍋の目止め
Unglazed clay is porous until rice starch seals it — one simmer, once.
漆器の手入れ
Dishwasher, microwave, sunlight. All normal, all irreversible on urushi.
片刃と利き手
Ground on one side only. The wrong side does not cut badly — it does not work.
土鍋とIH
Induction heats metal, not clay. Most donabe never get warm — and cannot be converted.
熊野筆の毛
Not a quality ladder. Natural hair holds powder; synthetic is built for cream and liquid.
砥石の番手
There is no dominant standard behind the number. Two #1000 stones can cut differently.
茶筅の穂数
Carved from a single piece, so a snapped tine is not a repair. The tine count is a spec, not a score.
錆と経年変化
One protects the blade, the other eats it. Scrubbing the wrong one leaves the knife worse off.
三徳・牛刀・菜切
Two of these are the same knife. And a nakiri suits either hand; the usuba it resembles does not.
ダマスカスの意味
The original ceased production around 1900. Since 1973 the word has meant pattern welding — decoration.
白紙と青紙
Blue holds an edge longer and is harder to sharpen. Which is better depends on how often you sharpen.
抹茶の等級表示
ISO and Japanese labelling define how matcha is made. Neither defines a grade.
硬度と刃角
Western knives sit at 52–58 and 20–22°; harder steel is what permits 15–18°. Higher is a different bargain.
まな板と刃
Glass dents, rolls and chips edges rapidly. Wood is self-healing — but grain matters more than "hardwood".
刃物を贈るとき
A gifted knife is said to sever the relationship. The custom is that the recipient hands back a coin.
金継ぎのキット
Real urushi cures in a humid box over days to weeks. A kit that sets in an hour is something else.
沈香と伽羅
The scent exists because the tree was infected. Uninfected wood is pale and light — whatever was added.
箸の形と作法
Pointed where Chinese ones are blunt. And two ordinary gestures read as funeral rites.
墨と膠
Sumi is soot held by animal glue. India ink needs no binder and dries waterproof on its own.
柄の木と嵌合
Friction-fitted, not bonded — so it can be replaced. And a D-shaped handle is made for one hand.
釉の上か下か
The body is impermeable. It is the decoration that is exposed — and you can feel which kind it is.
硬化した漆
Uncured urushi gives most people a rash. Cured, reactions are possible but less common.
刃こぼれ
Repair is subtraction — grind past the chip on a coarse stone, then work back up the grits.
