ItsuoDoi土井逸夫

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The story

Itsuo Doi (土井逸夫) is a Sakai forging blacksmith — a 鍛冶師 — on the craftsman roster of Aoki Hamono, the Sakai maker behind the Sakai Takayuki brand. In Sakai's knife-making tradition, forging and sharpening are separate professions practised by different specialists; Doi stands on the forging side, hammer-welding and shaping blades that other masters then grind and finish. Aoki's roster lists his specialty simply as 打物 — forged work.

What he is known for, above all, is Aogami #2 — and how gently he treats it. The Doi family technique is low-temperature forging: hotter steel moves faster under the hammer, but it burns carbon out of the edge. Doi forges cool — judging the steel by flame colour rather than a thermometer, at roughly 850°C — so the carbon stays where the edge needs it. Suisin, which builds its Hayate line on the inherited Doi process, describes it as low-temperature joining with controlled hammer forging on Yasuki Blue #2. His prestige work is single-bevel — yanagiba and their kin — though he forges double-bevel too: the maker attributes the Homura Guren kurouchi series (petty, nakiri, gyuto in Blue #2) to his hammer, its "red lotus" name taken from the colour of pine-charcoal flames in the Doi forge.

His signature series is 飛燕 — Hien, "flying swallow" — part of Sakai Takayuki's 四神 (Four Gods) series. The maker's own page calls it a katana-evoking Blue #2 blade and credits it to "the Sakai smith Itsuo Doi, who inherited the secret techniques across three generations". It is a kengata yanagiba with a gently curved spine, wider and heavier than a standard yanagiba, forged by Doi and traditionally sharpened by master sharpener Mitsuo Yamatsuka. Its 四神 sibling Genbu — a mirror-finished sakimaru takohiki in retailer listings — carries the same DNA. For years he was also engaged on the brand's Tokujō (特上) line; current listings attribute Tokujō production to the Togashi workshop, so we treat that chapter as history rather than present tense.

He is the son of the late Keijiro Doi (土井敬次郎), one of Sakai's most celebrated blacksmiths — the smith behind Sakai Takayuki's Blue #2 yanagiba for many years, certified a Traditional Craftsman in the 1980s per workshop records, and mourned by the trade when he died in November 2017, aged 90. Aoki Hamono's craftsman page records the succession directly: Itsuo "studied under his father, praised as a master craftsman, and acquired the secret techniques" of the Doi forge, entering it at 24 — a forging career now past fifty years.

Enthusiast forums discuss him with the honesty we like: consistent praise for the Blue #2 heat treatment — "Doi's Blue #2 is excellent"; "underrated as hell"; a preference for his single bevels — alongside fair notes that some grinds run stout and fit-and-finish varies. We'd rather show you that conversation than sand it down.

A note on records: several retail sites — including specialist ones — describe Doi as a certified 伝統工芸士 (Traditional Craftsman, 2013). We could not corroborate that in any official registry, and Aoki's own roster does not carry the designation against his name while marking six of his colleagues with it — his father held it — so we do not repeat it as fact.