How the Samurai Sword Shaped Modern Kitchen Knives

Japan’s famed kitchen knives—celebrated for their precision and craftsmanship—trace their origins to the samurai swords forged centuries ago, a legacy still evident in places like Tokyo’s Kappabashi Kitchen Street. Here, the sound of knife sharpening rings out on the sidewalk. Rows of shiny blades sparkle in shop windows, and purveyors demonstrate how these knives can effortlessly shave a carrot into paper-thin strips.

“Japan was actually quite late getting into the Iron Age,” says Paul Martin, a historian and author on Japanese weaponry. Swordsmithing spread to Japan from mainland Asia, he says, and between the third and sixth centuries, Japan started producing its own double-edged swords.

During the Heian period (A.D. 794-1185), Japan became more culturally independent with flourishing artistic and literary scenes. The samurai class—elite warriors who served powerful landowners and lords—arose and developed curved swords called tachi used for cavalry. Later, shorter, curved swords called katana were created for infantry use and kept as a sidearm. These single-edged curved blades are part of what make Japanese swords unique.

Japanese weaponry is also distinguished by its steel. “A thousand years ago, Japan was very poor in iron ore,” says Martin. “But they discovered they had abundant amounts of iron sand.” A method of steelwork called tamahagane was developed, which involved smelting sands to create steel, then forging and folding the metal to remove impurities. The sword’s carbon content was then adjusted before it was hammered and shaped into the blade. Katanas are made this way to have a rigid and sharp cutting edge while the spine remains flexible to ensure durability.

Perhaps the most distinctive facet of samurai swords is their deep connection to symbolism and spirituality. “Japanese swords are primarily defined by the sophistication of the artistic culture that has grown up around them,” says Tumi Grendel Markan, an educator at the Bizen Osafune Sword Museum in Setouchi, Japan. For the samurai, he says, their swords were viewed as an extension of their soul and a symbol of status, honor, loyalty and discipline.

“Swords were never merely weapons, they were always spiritual items and objects,” says Martin. During the Edo period (1603-1868), a unified shogunate—a military-led government—ushered in a period of relative peace. Katanas were used more as art pieces and status symbols rather than for battle.

But samurai sword usage took a big blow at the end of the Edo period and the Boshin War in 1868, a civil war between forces loyal to the ruling shogunate and those seeking to restore imperial rule under the emperor. For the first time, Japanese fighters were exposed to more Western weaponry. Guns and cannons widely replaced the centuries of sword-based warfare. Furthermore, the following Meiji period (1868-1912) barred the open carrying of swords as part of broader efforts to dismantle the samurai class and modernize the country.

“Many swordsmiths made kitchen knives and things like that to supplement their income,” says Martin. Strict licensing laws following World War II also saw more sword-makers convert to cutlery or other sharp-edged items. Famous samurai sword foundries such as Nigara Kunitoshi and Shiro Kunimitsu shifted their focus to making knives.

During Japan’s industrialization, Western stainless steels were introduced into Japanese smithing, offering greater resistance to rust and making them more practical for daily use compared to tamahagane. While materials and production methods evolved, many elements of the blacksmithing tradition continued into knife-making, including long training periods, specialized techniques and an emphasis on craftsmanship.

Midori Shaffer, owner of Hasu-Seizo, a purveyor of Japanese knives, says that traditional blacksmith apprenticeships took around 10 years, and the profession was typically passed down through generations. Today, apprentices get more hands-on training and positions are given to people who show great interest and aptitude. One such master knife maker, Itsuo Doi, grew up watching his father pounding steel. Doi also decided to take up the craft and has been making knives for 50 years. Reflecting on his work, he emphasizes the value of user feedback, particularly how a knife performs and feels in practice.

“Many of the young smiths have taken a more scientific approach to the theoretical background of the craft, such as heat treatment and temperature management,” says Shaffer. “Preserving and passing on the craft is as important as developing it further and finding one’s own way of expression and technique.”