Yamaguchi

The soul of every katana begins with the perfect choice of steel.

Whether forged from modern alloys or traditional steels, each selection reflects our pursuit of performance in harmony with artistry.

This careful beginning sets the stage for extraordinary quality and a blade that honors both craftsmanship and tradition.

The swordsmith forges the steel into a rectangular billet.

It is heated until red-hot, hammered to half its thickness, folded, reheated, and hammered again.

This process is repeated many times.

With each cycle, impurities are removed, the material’s composition becomes uniform, and unique grain patterns begin to emerge.

Forged steel varies — some types offer excellent flexibility but lower hardness, while others provide high hardness but can be brittle.

To achieve both hardness and toughness, a high-hardness outer jacket is carefully wrapped around a flexible core steel.

This step requires exceptional skill, as poor fusion between the steels can trap air bubbles, compromising the blade’s integrity.

Once combined, the steel is forged into the basic shape of the katana.

If engraving is required, it is done at this stage — not at the final step as commonly believed.

Once the katana is quenched, it becomes too hard to carve.

This stage allows the swordsmith to incorporate symbols of personal belief or spiritual significance into the blade.

Quenching is a highly skilled process.

At this stage, the katana’s performance, hamon (temper line), and elegant curvature are all set permanently.

Any mistake at this point would mean the loss of all previous work.

Once forging is complete, the blade is entrusted to the polisher — a master of patience and precision.

With whetstones of many grits, the polisher carefully removes the surface layers, much like a sculptor.

Through this painstaking process, the katana’s hidden beauty emerges.

Its strength, sharpness, and the distinctive hamon — the sword’s signature — are finally unveiled.