Moroha-Zukuri Japanese Swords: A Complete History from Ancient Swords to Modern Works

Morohazukuri: "Swords with Blades on Both Sides"

Morohazukuri (also called ryouba or ryoubauzukuri) is a type of Japanese sword construction (cross-sectional shape) where the blade has edges on both sides (front and back). While typical Japanese swords (uchigatana, tachi, wakizashi) are single-edged (with blades on only one side), morohazukuri features sharp edges extending from the center line toward both sides. The cross-section takes on a diamond shape that is symmetrical from left to right, or close to a triangular shape.

In modern times, the idiom "morohano tsurugi" (a double-edged sword, meaning "having both benefits and harms") is widely known, but few people have detailed knowledge of morohazukuri as an actual sword form.

History of Morohazukuri: From Ancient Swords to the Kamakura Period

Yayoi to Kofun Period (Era of Straight Swords)

During the Yayoi to Kofun periods, when metal implements became widespread in the Japanese archipelago, swords existed primarily as imports from continental China or the Korean Peninsula, or as imitations thereof. Most swords of this era were chokuto (straight swords without curvature), with both morohazukuri and single-edged forms existing side by side.

Ancient Chinese swords (bronze and iron swords) often featured double edges, and this form was transmitted to Japan as well.

Nara to Early Heian Period (Ancient Swords)

During the Nara period through the early Heian period, when Japan's unique forging techniques developed, swords from the period called jokoto (ancient swords) were produced. Both single-edged and double-edged forms existed during this era as well.

The haranuki is believed to be one type of double-edged short sword form carried by samurai during the Heian period. It is said that both edges were used to reduce friction when withdrawing the blade after cutting.

Decline from the Kamakura Period Onward

As the tachi form became established during the Kamakura period and the "curved single-edged blade" became the standard for Japanese swords, morohazukuri blades ceased to be made except for certain specialized purposes (primarily short swords and ceremonial blades).

The following reasons are cited for this change:

• Single-edged blades concentrate cutting power more effectively and are more practical
• Double-edged blades are difficult to manufacture while maintaining equal edge quality on both sides
• Japan's unique forging techniques became optimized for single-edged blades

Representative Types of Morohazukuri Swords

Double-Edged Short Swords

During the Kamakura to Nanboku-cho periods, some specialized short swords that functioned as yoroidooshi (armor-piercing blades) adopted the morohazukuri form. For thrusting between gaps in armor, double-edged blades had advantages over single-edged blades when withdrawing.

Gomabaski and Kogai

Some kogai, which functioned as everyday portable implements (used for hairstyling, ear cleaning, etc.), had double-edged or sword-like (tsuruginarai) forms. These had more of a "decorative and weapon" character than that of "practical bladed tools."

Ceremonial Swords and Sacred Swords

Among the sacred swords (jinto) dedicated as sacred treasures to shrines and the ceremonial swords (reitou) used in imperial court ceremonies, there are straight double-edged swords that inherited ancient forms. The Kusanagi no Tsurugi, said to be one of the Three Imperial Regalia, is sometimes described in legend as a "sharp double-edged sword," and some scholars interpret this as a morohazukuri straight sword.

Technical Characteristics of Morohazukuri

Difficulty of Manufacture

Morohazukuri is more difficult to manufacture compared to single-edged blades. The reasons are as follows:

• It is necessary to create edges with equal sharpness on both sides
• Symmetrical hardening of both sides makes managing the blade's curvature more complex
• Precision is required to maintain uniform thickness on both sides while shaping

Unique Characteristics of the Hamon

The hamon of morohazukuri differs from single-edged blades, with hamon appearing on both sides. The beauty of this symmetrical hamon possesses its own aesthetic that single-edged blades do not have.

Modern Morohazukuri: Archaism and Artistic Expression

Among modern sword smiths, there are works that have taken on the challenge of morohazukuri as an ancient form. There are cases where master swordsmiths of the caliber of Living National Treasures have presented straight-sword forms of morohazukuri based on research and restoration of ancient techniques, and these are evaluated as works that combine both "technical research of ancient swords" and "exploration of the possibilities of Japanese swords."

Even today, straight double-edged swords are sometimes created as dedication swords for shrines. As special-order pieces made for imperial court ceremonies and major shrine festivals, the ancient forms continue to be passed down.

Notes on Appreciation: Evaluating "Rarity"

When appreciating morohazukuri swords, it is necessary to be careful about how "rarity" is understood. Morohazukuri represents a minority form among Japanese swords and carries added value as a "rare form" for collectors. However, rarity alone does not drive up prices, and the quality of manufacture, period, and smith determine the price just as with single-edged swords.

Conclusion: What Morohazukuri Tells Us About the Origins of Japanese Swords

Morohazukuri Japanese swords tell the story of their origins before the establishment of Japanese swords as "curved single-edged blades." They represent a "preliminary stage" in the process by which ancient sword forms, influenced by continental culture, changed shape alongside the development of Japan's unique forging techniques and ultimately evolved into curved single-edged tachi and uchigatana.

While few morohazukuri swords remain in the modern era, their existence serves as a key to understanding the full picture of Japanese sword history. For collectors who wish to add the dimension of "origins" to their Japanese sword collections, morohazukuri will be a choice of special significance.