--- title: How Japanese Dried Bonito Is Made | daily.dev description: Katsuobushi, Japanese dried bonito said to be the world's hardest food, is made using a hand-fired smoking method called 'tebiyama'. At Kanesa Katsuobushi... canonical: https://daily.dev/posts/how-japanese-dried-bonito-is-made-uyssqo5gy twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: How Japanese Dried Bonito Is Made | daily.dev og:description: Katsuobushi, Japanese dried bonito said to be the world's hardest food, is made using a hand-fired smoking method called 'tebiyama'. At Kanesa Katsuobushi... og:url: https://daily.dev/posts/how-japanese-dried-bonito-is-made-uyssqo5gy og:image: https://api.daily.dev/og/posts/uyssqO5gy.png og:image:alt: How Japanese Dried Bonito Is Made og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # How Japanese Dried Bonito Is Made **[Hacker News](https://daily.dev/sources/hn)** · 2 min read · 0 upvotes · 0 comments ## Summary Katsuobushi, Japanese dried bonito said to be the world's hardest food, is made using a hand-fired smoking method called 'tebiyama'. At Kanesa Katsuobushi Shoten, a workshop founded in 1882, 5th-generation craftsman Yasuhisa Serizawa fillets and boils fresh bonito for 90 minutes. The fish is then smoke-dried more than 10 times over a hand-tended wood fire, repaired with bonito paste, fermented with koji mold, and sun-dried for months. The whole process takes over half a year until the fish becomes as hard as wood. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is the tebiyama method for making katsuobushi? Tebiyama is a 200-to-300-year-old hand-fired smoking technique from the Tago district of West Izu, Japan, used to make katsuobushi (dried bonito). It involves digging a vertical hole about 2 meters deep, burning raw Izu wood like oak, sawtooth oak, and cherry from the bottom, and smoking the fish with an open flame's high heat, which locks in umami flavor. _Readers curious about traditional food science can find process deep-dives like this one on daily.dev._ ### How long does it take to make katsuobushi from fresh bonito? Making katsuobushi takes over half a year, from fresh catch to finished product. The fish is filleted and boiled for 90 minutes, smoke-dried more than 10 times over a hand-tended wood fire, repaired with bonito paste, fermented with koji mold, and then sun-dried for months until it becomes as hard as wood and shines like a jewel. _Anyone fascinated by slow, traditional production methods can browse similar craft stories on daily.dev._ ## Community take How the wider developer community reacted, aggregated from 1 discussion and 50 comments across hackernews (as of 2026-10-25). **TL;DR:** Discussion is largely admiring of the craftsmanship and tradition behind katsuobushi, with tangents into fish allergies, food science, and the history/authenticity of the technique; a few raise minor health or clarity concerns. **Sentiment:** 65% positive · 30% mixed · 5% skeptical **The case for** - Many shared personal appreciation for the flavor and versatility of bonito flakes and dashi. - Several praised the painstaking, highly manual craftsmanship (deboning, fire-tending) as admirable and almost artistic. - One detailed firsthand market/restaurant anecdote was called excellent, human-grounded writing. **The pushback** - A debate arose over whether a shop founded in 1882 can legitimately claim an 'Edo period' method since the era ended in 1868. - One commenter raised concern about benzopyrene (a carcinogen) from the smoking process. - One commenter felt the article didn't clearly define its subject for newcomers. **By community** - hackernews (positive): Mostly admiring and curious reactions about the craft and flavor, with a side debate on historical authenticity and a tangent about fish allergies and protein science. **Hottest debate:** Whether a shop founded in 1882 can truthfully be described as using 'Edo period' techniques given the era ended in 1868. **Open questions** - How did artisans originally discover this specific multi-step smoking, fermenting, and sun-drying process? - Is there a modern mechanized alternative to hand-deboning the fillets? **Highlights** > In the old Tsukiji market you walked past wooden boxes of the flakes wafting gently in the breeze and saw people milling them with green enamelled powered industrial bench planes, while cooking gas powered market trolleys trundled around, with curious drum like round control panels shifting frozen tuna sides and boxes of abalone. I've never seen those motorised carts anywhere else. the stuff we buy in packets here in oz must suffer in transit and packaging, they are shattered fragments but they still waft gently in the steam of a bowl of salmon and rice. The bonito shavings reminded me of the litter around a wood turners lathe. Waste there, but here the point of the exercise. I think I've had them served as a garnish on Oden. They dance. > — [ggm on hackernews · 3 comments](https://news.ycombinator.com/item?id=50229091) > *1882 Is this supposed to be some insightful criticism? They've been making the same product for 144 years, and managed to retain the technique from an era only 14 years prior. That's an achievement. If a place started doing the same in 2017, guess what, they could still make it like they did in the Edo period. Apart from a bit of machinery for lifting, and starting with frozen fish (which they thaw first anyway), it's basically all manual labour, including adjusting the fire temperature. > — [Walf on hackernews · 1 comments](https://news.ycombinator.com/item?id=50229770) > I was a bit put off katsuobushi when I read that because of the tar in the smoking process it can contain carcinogenic benzopyrene > — [Jarmsy on hackernews · 1 comments](https://news.ycombinator.com/item?id=50231983) > > I'm allergic to fish... I'd guess that your allergy is to some class of proteins in the fish - and that the production steps for dried bonito (and maybe the time required) denature or destroy those proteins. > — [bell-cot on hackernews](https://news.ycombinator.com/item?id=50229537) > Almost certainly it was an incremental discovery process, first cooking and/or fumigating tuna for other consumption, then extending its shelf life by fermentation and/or sun-drying, discovering that evening out the exterior with paste helps extend it, then solving the problem that extended drying leads to hard consistency by shaving off very thin slices, stuff like that. They didn’t set out with “oh we need very thin dried tuna slices for dashi and seasoning” and then invented a whole process for that. > — [layer8 on hackernews](https://news.ycombinator.com/item?id=50233968) **Source threads** - [hackernews](https://news.ycombinator.com/item?id=50193936) · 150 points · 50 comments ## Similar posts on daily.dev - [Founders Fund's outlier bet on humanely killed fish](https://daily.dev/posts/founders-fund-s-outlier-bet-on-humanely-killed-fish-qk76wh6mk) · TechCrunch · 0 upvotes · 0 comments - [Anime-Style Cooking 3D Animation Created with Blender](https://daily.dev/posts/anime-style-cooking-3d-animation-created-with-blender-m56bwxlle) · 80 LEVEL · 9 upvotes · 0 comments - [Burning Wood To Brew Wood To Preserve Wood : Pine Tar](https://daily.dev/posts/burning-wood-to-brew-wood-to-preserve-wood-pine-tar-b86tmm13h) · Hackaday · 0 upvotes · 0 comments - [Schneier on Security](https://daily.dev/posts/schneier-on-security-pul6wxtno) · Schneier on Security · 0 upvotes · 0 comments - [What on Earth Is Dekton?](https://daily.dev/posts/what-on-earth-is-dekton--td1nfeisu) · Hacker News · 0 upvotes · 0 comments --- [View this post on daily.dev](https://daily.dev/posts/how-japanese-dried-bonito-is-made-uyssqo5gy) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"How Japanese Dried Bonito Is Made","url":"https://daily.dev/posts/how-japanese-dried-bonito-is-made-uyssqo5gy","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/how-japanese-dried-bonito-is-made-uyssqo5gy"},"datePublished":"2026-10-25T13:29:50.688Z","dateModified":"2026-10-25T17:45:46.436Z","description":"Katsuobushi, Japanese dried bonito said to be the world's hardest food, is made using a hand-fired smoking method called 'tebiyama'. 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