硬化した漆
Uncured urushi is an allergen that gives most people a rash. Cured urushi is the same compound after it has polymerised, and that changes the answer.
Wikipedia’s article on the lacquer tree describes the process and the outcome together. The sap contains urushiol, an allergenic irritant, and curing the applied sap means drying it in a warm humid chamber for 12 to 24 hours, during which the urushiol polymerises to form a clear, hard, waterproof surface. On the finished state it is direct: once hardened, reactions are possible but less common. Tableware is listed among the common applications.
So the honest answer has two parts. Cured urushi is not the same hazard as the liquid — polymerisation is what a finish is — but "less common" is not "impossible", and the article does not say otherwise. People who react to poison ivy share the sensitivity, since urushiol is what makes poison ivy what it is, and a small number of people do react to finished lacquerware.
Two things follow that are practical rather than theoretical. Damage matters: a chipped or worn lacquer surface is no longer the continuous cured film the description assumes, which is one more reason the dishwasher is worth avoiding beyond the cosmetic damage. And the literature cited in the lacquerware article includes work on heat treatment rendering Japanese lacquerware hypoallergenic, which tells you the question has been taken seriously enough to study rather than settled by assertion.
A finished piece from an established maker has cured — that is what makes it a finished piece. The situations worth more care are the ones where curing is in question or the film is broken: a repair you have done yourself, a kit whose contents you cannot identify, or a bowl whose lacquer has chipped through. If you know you react badly to poison ivy, that is the same compound, and worth weighing before buying rather than after.
This page reports what the sources say and is not medical advice. If you have a known urushiol sensitivity, the question is one for a doctor rather than for a craft site.
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.
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.
刃こぼれ
Repair is subtraction — grind past the chip on a coarse stone, then work back up the grits.