Ask any Japanese food lover to name the country’s smelliest dish and you’ll almost certainly hear one word: kusaya. This sun-dried, fermented fish from the remote Izu Islands south of Tokyo has a smell that’s been compared to rotting garbage, old gym socks, and low tide at its worst — and yet islanders have been eating it for over 400 years, and a growing number of curious travelers now seek it out on purpose. If you want to taste one of Japan’s most extreme regional foods and understand why people defend it so fiercely, here’s what you need to know before you go looking.
What Is Kusaya, Exactly?
Kusaya is made by soaking fish — traditionally kusaya mukuro (a type of scad/horse mackerel) or tobiuo (flying fish) — in a briny fermentation liquid called kusaya-jiru before drying it in the sun and sea wind. What makes it unique is that this brine isn’t made fresh each time. Individual households and small producers on the islands reuse and top up the same liquid for generations, sometimes for over a century, so each producer’s brine carries its own distinct colony of bacteria and yeast, like a sourdough starter passed down through a family. That’s also why the smell varies noticeably from one producer, and even one island, to the next.
Once dried, the fish is almost always eaten grilled rather than raw. Grilling knocks back some of the ammonia-like sharpness, and what’s left underneath is a deeply savory, almost cheese-like umami that fans compare to a strong blue cheese or well-aged natto. It’s traditionally torn into strips by hand and eaten as an otsumami (drinking snack), often with a smear of Japanese mayonnaise.
Why It Smells So Strong (And Why Locals Love It Anyway)
The odor comes from the same long fermentation that builds the flavor — the bacteria in the brine produce volatile sulfur and nitrogen compounds as they break down the fish’s proteins. In international “smelliest food” rankings, kusaya is regularly mentioned alongside Sweden’s surströmming and Korea’s hongeohoe. On the islands, though, it’s simply home cooking: a practical way to preserve fish for the long months when boats couldn’t easily reach the mainland, built around the trial and error of generations of fishing families.
If you’re the type of traveler who already seeks out other intensely regional dishes — the way grilled whole smelt shows up on izakaya menus across the country, as covered in our guide to shishamo and where to order it — kusaya belongs on that same list, just several notches further out on the intensity scale.
Getting to the Izu Islands Where Kusaya Is Made
Kusaya comes specifically from the Izu Islands chain south of Tokyo Bay, with Niijima, Shikinejima, Kozushima, and Hachijojima as the main producing islands. All of them are reachable from Tokyo:
- By ferry: Tokai Kisen operates large overnight ferries and faster jet ferries from Takeshiba Pier in Tokyo. The high-speed jet ferry reaches Niijima, Shikinejima, or Kozushima in roughly 3–4 hours, with one-way fares typically in the ¥9,000–11,000 range. The slower overnight ferry to Hachijojima takes around 10 hours and costs roughly ¥9,000–10,000 in second class, departing in the evening and arriving the next morning — a cheap way to combine transport with a night’s sleep.
- By air: ANA flies Haneda to Hachijojima in about 55 minutes. Fares vary widely with how far ahead you book, but expect somewhere around ¥18,000–23,000 one way at standard pricing, with discount fares available if booked early.
There’s no bullet train or bridge shortcut here — reaching kusaya country requires the same deliberate, slightly old-fashioned travel planning you’d use for other far-flung Japanese destinations, similar in spirit to island-hopping routes like the one described in our guide to Setoda on the Shimanami Kaido.
Best Season and Timing to Visit
Kusaya is made year-round, but the traditional drying process relies on sun and wind, so production ramps up in the drier months from autumn through spring. Summer (July–September) is peak tourist season for the Izu Islands thanks to diving and beach weather, which means better ferry frequency and more open shops, but also higher humidity that can intensify the smell in small, unventilated izakayas. If your priority is comfortable sightseeing alongside the food, aim for late spring (May) or autumn (October–November), when the seas are calmer, the ferries run reliably, and the smell is a bit more contained.
Where to Try Kusaya — On the Islands and in Tokyo
On the islands: Small family-run shokudo (diners) and minshuku (guesthouses) on Niijima and Hachijojima serve grilled kusaya as a set-meal side or standalone otsumami, generally priced around ¥500–900 for a small grilled portion. Island general stores and ferry-terminal gift shops also sell vacuum-packed dried kusaya to take home, typically ¥800–1,500 depending on the fish and portion size — note that it needs to be grilled before eating, not eaten raw out of the pack.
In Tokyo: You don’t need to fly or sail to try it once. Izakaya chains and standalone shops specializing in regional and island cuisine — the kind of place with a long handwritten menu and a strong focus on sake or shochu — often list kusaya simply as “くさや” (kusaya) for roughly ¥500–900 a plate. It’s worth calling ahead or checking a current menu photo online, since not every izakaya stocks it regularly; ask staff if they have it before you sit down if it’s the main reason for your visit. If you’re already building a night around interesting drinks, pair it with a glass of something unusual rather than the usual highball — our guide to natural wine bars in Tokyo covers spots where an adventurous palate is already the house style, though a classic Hachijojima mugi (barley) shochu is the more traditional match for kusaya.
Common Mistakes First-Timers Make
- Smelling it raw before it’s grilled. Unopened, cold, undrilled kusaya smells dramatically worse than the finished grilled dish. Don’t judge it — or decide not to order it — based on an unheated packet or a shop’s storage room.
- Grilling it indoors in a small apartment. If you buy dried kusaya to cook yourself, grill it outdoors, near an open window, or on a well-ventilated balcony. The smell clings to curtains, clothes, and small kitchens for days, and most Japanese rental agreements and shared accommodations will not thank you for it.
- Expecting it to taste like it smells. This is the single biggest surprise for first-timers — the flavor is far milder and more savory than the smell suggests, closer to an intense dried fish or hard cheese than anything resembling the odor.
- Skipping the mayonnaise. It’s not just garnish — the fat and acidity round out the saltiness and are the standard way it’s served across the islands.
Budget, Mid-Range, and Splurge Ways to Try It
Budget: Order a small plate (¥500–900) at a Tokyo izakaya that lists island cuisine — no travel required, lowest commitment.
Mid-range: Take the overnight ferry to Hachijojima (around ¥9,000–10,000 one way) and eat it fresh at a local shokudo alongside other island specialties like island-grown passionfruit and sashimi, turning the trip into a proper two- or three-day island getaway.
Splurge: Fly to Hachijojima, stay at a ryokan with a kaiseki-style dinner that features kusaya as one course among many, and bring home vacuum-packed kusaya plus a bottle of local mugi shochu as a (strong-smelling, double-bagged-for-your-suitcase) souvenir.
However you try it, go in with an open mind and a willingness to separate the smell from the taste — it’s one of the few foods in Japan where the two genuinely don’t match, and that gap is exactly what’s made kusaya a point of pride on the Izu Islands for centuries.