Any allergy or diet, understood in Japanese.

Dashi stock · だし / かつおだし

Dashi, the base stock in nearly all Japanese cooking, is usually made from dried bonito (skipjack tuna) or other fish, so soups, broths, sauces, and simmered dishes are a hidden source of fish even when no fish is visible.

Bonito-based dashi (katsuobushi, dried skipjack tuna) is the common form and contains fish. Kombu (kelp) and shiitake dashi are fish-free, so the allergen depends on preparation. Travelers should not assume a clear-looking broth is fish-free.

Soy sauce · 醤油 (shoyu)

Standard Japanese soy sauce (koikuchi shoyu) is brewed with wheat in roughly equal parts to soybeans, so the table soy sauce served with sushi, sashimi, and dumplings contains gluten and is unsafe for celiacs unless it is specifically tamari or labeled gluten-free.

Tamari is usually wheat-free and the standard gluten-free swap, but some tamari brands add small amounts of wheat, so the label must still be checked. Wheat-allergic (not just celiac) travelers should treat standard shoyu as a wheat exposure.

Imitation crab (kanikama) · カニカマ / 蒲鉾

In Japan, stick-type imitation crab (kanikama) used in sushi and salads looks like plain seafood but commonly hides wheat in its starch along with egg white, soy, and real crab extract, so check the label of each brand before eating.

Ingredients vary by brand and product type. The wheat plus egg-white combination is typical of stick-type kanikama used for sushi, but some products are explicitly egg-free and some flake or salad types omit wheat. Crab extract and soy are near-universal, and the surimi base is fish. Always read the per-product allergen label.

Soba noodles · 二八蕎麦 (ni-hachi soba)

Most soba sold and served in Japan, including the standard ni-hachi style, is roughly 80% buckwheat and 20% wheat flour, so ordinary soba contains gluten and wheat unless it is specifically labeled juwari (十割, 100% buckwheat).

Ni-hachi (80/20) is the professional default; juwari (十割) soba is 100% buckwheat and contains no wheat. Even 100%-buckwheat soba is often made or boiled in shared wheat facilities or water, so confirm both the recipe and cross-contamination rather than assuming buckwheat means safe.

Shabu-shabu sesame dipping sauce (goma dare) · ごまだれ / 胡麻だれ

At a shabu-shabu hot pot, one of the two standard dipping sauces (goma dare) is built on ground sesame paste, so choosing the wrong bowl delivers a heavy sesame dose with no visible seeds to warn you.

Goma dare is made from neri goma (sesame paste), so the sesame is fully ground in and not visible as seeds. Shabu-shabu is conventionally served with two dipping sauces, sesame (goma dare) and citrus ponzu; the sesame one is the hazard. The sauce also commonly contains soy sauce and dashi.