Sumi and India ink are both soot and both black, and they behave differently once dry. The reason is in what holds the soot together.
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Wikipedia describes the two compositions side by side. An inkstick is made mainly of soot and animal glue, and ink is made by grinding it against an inkstone with a little water; most inksticks use soot from pine or oil combined with animal glue. Basic India ink is fine soot, known as lampblack, combined with water — and no binder is necessary, because the carbon is in colloidal suspension and forms a waterproof layer after drying.
That is the difference in one line: India ink can be waterproof without a binder, and a binder such as gelatin or shellac is added to make it more durable rather than to make it work. Sumi depends on animal glue to hold the soot at all. So “is it waterproof” is not a property of the word sumi; it is a property of the particular ink, and the article is explicit that India ink itself may be waterproof or non-waterproof depending on whether a binder is used.
The grinding is not ceremony either. Concentration is controlled by how long and how hard the stick is ground, which is how tonal range is produced in ink wash painting — varying ink density by differential grinding, and by varying load and pressure within a single stroke. Prepared liquid ink exists and is normal in Japan, sold as bokuju; what it costs you is that control.
Suzuka ink is one of the crafts designated by Japan’s Ministry of Economy, Trade and Industry, alongside the Nara brushes and the Kumano brushes covered elsewhere on this site. For the practical question, though, the designation is not the field to read: look for the binder, or for an explicit statement about water resistance. A bottle that says neither has not answered the question people most often ask about it.
No shop link here. Which ink suits you depends on whether you are writing, painting, or making something that has to survive being framed behind glass or getting damp — and the sources above describe the materials rather than rank the products.
SourcesThe scent exists because the tree was infected. Uninfected wood is pale and light — whatever was added.
There is no dominant standard behind the number. Two #1000 stones can cut differently.
Glass dents, rolls and chips edges rapidly. Wood is self-healing — but grain matters more than "hardwood".
Two of these are the same knife. And a nakiri suits either hand; the usuba it resembles does not.
JIS defines it — and the definition says most washi today is machine-made from chemical pulp.
Carved from a single piece, so a snapped tine is not a repair. The tine count is a spec, not a score.
Not a quality ladder. Natural hair holds powder; synthetic is built for cream and liquid.
ISO and Japanese labelling define how matcha is made. Neither defines a grade.
Ground on one side only. The wrong side does not cut badly — it does not work.
Blue holds an edge longer and is harder to sharpen. Which is better depends on how often you sharpen.
One protects the blade, the other eats it. Scrubbing the wrong one leaves the knife worse off.
Western knives sit at 52–58 and 20–22°; harder steel is what permits 15–18°. Higher is a different bargain.
Repair is subtraction — grind past the chip on a coarse stone, then work back up the grits.
A gifted knife is said to sever the relationship. The custom is that the recipient hands back a coin.
Friction-fitted, not bonded — so it can be replaced. And a D-shaped handle is made for one hand.
The usual fix starts by soaking it. A seiro maker calls soaking strictly forbidden.
Dishwasher, microwave, sunlight. All normal, all irreversible on urushi.
Uncured urushi gives most people a rash. Cured, reactions are possible but less common.
A prefectural institute put eleven lacquer films through JIS Z 2801. Most came back undetectable.
The original ceased production around 1900. Since 1973 the word has meant pattern welding — decoration.
It conducts heat badly. That is the product — and it is also why it cracks.
Unglazed clay is porous until rice starch seals it — one simmer, once.
Induction heats metal, not clay. Most donabe never get warm — and cannot be converted.
Real urushi cures in a humid box over days to weeks. A kit that sets in an hour is something else.
Not urushi against epoxy. Whether the material states food-contact compliance.
Pointed where Chinese ones are blunt. And two ordinary gestures read as funeral rites.
The body is impermeable. It is the decoration that is exposed — and you can feel which kind it is.
One boils water and gives you iron. Putting the other on heat cracks its lining for good.
The spots appear in the first week. The makers’ association says do not take them off.
The form is settled by a 2003 paper. The amount is not settled by anything.
