Discover the heritage of Sakai Uchihamono, from the city's early ironworking traditions and tobacco-cutting knives to the specialised blacksmiths and sharpeners who continue making Japanese kitchen knives today.

In the city of Sakai, Osaka Prefecture, the making of blades has a history that reaches far beyond the modern kitchen.

Over centuries, the region's craftsmen have worked with iron and steel to produce tools suited to the needs of their time.

Among the most recognised products of this tradition are Sakai Uchihamono—Sakai forged blades.

Today, Sakai is particularly associated with Japanese kitchen knives used by professional chefs and cooking enthusiasts.

Yet the significance of these knives extends beyond their cutting performance.

Their history reflects changes in Japanese society, the development of food culture, and a system of specialised craftsmanship.

To understand a Sakai knife is to look beyond its polished surface and consider the people, knowledge, and traditions behind it.

Sakai's history of metalworking is often traced to the Kofun period, when large burial mounds were constructed in the region.

The Mozu burial mounds, including the enormous mound traditionally associated with Emperor Nintoku, remain important reminders of this early history.

Constructing such monuments required substantial labour and the use of tools.

Local accounts of Sakai's blade-making heritage connect these activities with the development of ironworking skills in the area.

However, it is important to distinguish this early metalworking history from the later, more clearly documented development of Sakai's specialised blade industry.

The tools, production methods, and social conditions of the Kofun period were very different from those of modern knife making.

Sakai's history is therefore best understood as a long development of metalworking traditions rather than an unchanged craft continuing in exactly the same form for more than a thousand years.

What connects these periods is the importance of skilled people working with metal to meet practical needs.

One important chapter in Sakai's blade-making history concerns tobacco-cutting knives.

As tobacco use spread in Japan during the early modern period, specialised knives were needed to cut tobacco leaves into fine strips.

Sakai craftsmen developed a reputation for producing these blades.

Historical accounts of the industry describe recognition by the Tokugawa shogunate, including the use of the name Sakai Kiwame in connection with Sakai tobacco knives.

This history illustrates how blade-making skills could be adapted to changing demand.

The importance of tobacco knives was not simply that they were sharp.

They also required consistent construction and cutting performance for a specialised task.

The development of this industry contributed to Sakai's reputation as a centre of skilled blade production.

It is an example of how a practical tool can become part of a region's cultural and industrial identity.

As Japanese food culture developed, cooks required tools suited to different ingredients and techniques.

Fish preparation, vegetable cutting, and the presentation of food all created distinct demands.

Sakai's knife-making traditions evolved alongside these culinary practices.

The yanagiba became associated with controlled slicing, particularly in sashimi preparation.

The deba developed as a substantial knife suited to particular fish preparation tasks.

The usuba became an important tool for specialised vegetable cutting.

These knives differ in thickness, blade geometry, weight, and intended use.

Their forms reflect practical requirements rather than decoration alone.

The relationship between cooks and craftsmen has been an important part of this development.

Culinary techniques influence the tools people need, while the characteristics of those tools can also shape how particular tasks are performed.

This connection helps explain why Japanese kitchen knives include so many specialised forms.

Traditional Sakai kitchen knives are particularly associated with single-edged (single-bevel) construction.

Unlike a conventional symmetrical double-edged (double-bevel) knife, a traditional single-edged blade has different geometry on its two sides.

A broad cutting bevel is formed on one side.

The reverse side often includes a shallow concave area known as urasuki.

This construction supports particular cutting and sharpening techniques.

For example, the geometry of a yanagiba is intended to help produce controlled slices of fish.

However, single-edged construction does not automatically make a knife sharper than every double-edged design.

Cutting performance depends on edge geometry, blade thickness, sharpening, steel properties, and the user's technique.

Similarly, a clean cut may contribute to the appearance and texture of prepared food, but it does not guarantee superior flavour.

The value of single-edged construction lies in how well it serves a particular culinary purpose.

One of the defining characteristics of traditional Sakai knife making is the division of labour among specialised craftsmen.

The blacksmith shapes and heat-treats the blade.

The sharpener establishes its geometry, refines the cutting surfaces, and forms the cutting edge.

Handle makers and other specialists may contribute to the completed knife.

These are different areas of expertise.

A blacksmith must understand how the steel responds to heat and deformation.

A sharpener must understand how geometry and finishing influence cutting performance.

A handle maker must consider material, fit, and the way the knife will feel in the hand.

The final knife brings these skills together.

Not every Sakai knife follows exactly the same production arrangement, and different workshops may organise their work differently.

Nevertheless, this tradition of specialisation remains central to understanding the character of Sakai Uchihamono.

The finished knife is often the result of several skilled people contributing to a shared purpose.

Forging is an important process in many traditional Sakai knives.

The blacksmith heats and shapes the material to establish the blade's form.

Depending on the construction and steel, forging may also be part of preparing the material for subsequent processing.

However, repeated hammering does not simply compress steel into a permanently denser material.

The properties of the finished blade depend on the material, forging conditions, heat treatment, and subsequent finishing.

Heat treatment is particularly important.

Hardening and tempering influence the blade's microstructure and mechanical properties.

The appropriate process differs between carbon steels, stainless steels, and other alloys.

An experienced craftsman must understand how each material responds.

The goal is not to achieve the highest possible hardness.

It is to develop properties appropriate to the knife's intended use.

This requires both technical knowledge and careful control.

The sharpener's work is fundamental to the performance of many Sakai knives.

Sharpening involves far more than making the edge feel sharp.

The craftsman must consider the blade's overall geometry, the cutting bevel, the relationship between the two sides, and the intended cutting technique.

A small difference in thickness or angle can influence how the knife moves through food.

For traditional single-edged knives, maintaining the relationship between the broad bevel and the back of the blade is particularly important.

Finishing also influences the appearance of the knife.

Mirror polishing, traditional kasumi finishes, and other surface treatments create different visual characteristics.

However, a more reflective surface does not automatically guarantee better cutting performance.

The quality of sharpening should be considered in relation to the blade's purpose.

In Sakai, this specialised knowledge is an essential part of the finished knife's value.

Japanese cuisine has given rise to a wide range of specialised knife designs.

Alongside familiar forms such as yanagiba, deba, and usuba, there are knives developed for more specific ingredients and tasks.

A fuguhiki is associated with delicate slicing of fugu.

An unagisaki is used in eel preparation, with regional variations in its form.

Honegiri knives are associated with cutting the fine bones of fish such as hamo.

Specialised noodle-cutting knives represent another category of Japanese cutting tools.

This variety reflects the diversity of Japanese culinary techniques.

It also demonstrates that a knife's design should be understood through its intended purpose.

The most versatile knife is not necessarily the best choice for every specialised task.

Likewise, a highly specialised knife may not be practical for everyday home cooking.

Understanding these differences helps cooks appreciate why so many forms have developed.

Traditional craft industries face the challenge of passing specialised skills to younger generations.

Sakai knife making is no exception.

Training a skilled blacksmith or sharpener requires time, practical experience, and access to knowledgeable teachers.

The work can be physically demanding, and developing advanced techniques may take many years.

Changes in consumer demand, manufacturing methods, and the availability of skilled workers also influence the future of the industry.

Preserving craftsmanship therefore requires more than admiration for its history.

It requires opportunities for training, continued work for craftsmen, and customers who understand the value of skilled production.

Modern equipment and traditional techniques need not always be opposites.

Different workshops may combine them in different ways, depending on the materials and products involved.

The essential question is whether the knowledge needed to make good knives can continue to be developed and passed on.

Tradition remains meaningful when people are able to practise it.

Today, Japanese kitchen knives are used in many countries.

For people living far from Japan, purchasing a Sakai knife can be an opportunity to encounter a craft they may never have seen firsthand.

But understanding the knife requires more than knowing its steel type or dimensions.

Who made the blade?

Who sharpened it?

What techniques were involved?

How should the knife be used and maintained?

These questions help connect the finished product with the people responsible for it.

At KIREAJI, our relationship with Shiroyama Knife Workshop allows us to introduce Sakai craftsmanship to customers beyond Japan.

We believe that the value of these knives is better understood when the work of the craftsmen is recognised.

Our purpose is not simply to present a Japanese knife as a luxury object.

It is to help people appreciate the knowledge, care, and practical skill behind the tool.

The history of Sakai Uchihamono connects early metalworking traditions, specialised tobacco knives, Japanese food culture, and the development of modern kitchen tools.

Across these changes, the importance of skilled craftsmanship has remained.

Blacksmiths, sharpeners, handle makers, and other specialists contribute different forms of knowledge to the finished knife.

Their work transforms steel and other materials into tools designed for particular purposes.

The beauty of a Sakai knife is not found only in its sharpness or polished surface.

It also lies in the decisions, experience, and cooperation behind its creation.

At KIREAJI, we hope to share that understanding with people around the world.

A Sakai knife is a practical tool, but it can also become a connection to the people and traditions that shaped it.

The most meaningful way to respect that tradition is to understand the knife, use it appropriately, and care for it over time.

In that way, the story of Sakai Uchihamono continues—not only in workshops in Japan, but also in the kitchens where these knives are used.