Bishu Osafune Morimitsu—The Peak of Oei Bizen, A Complete Overview of the Leading Bizen Sword Smith of Early Muromachi

The Oei Bizen Era and the Age of Bishu Osafune Morimitsu

The Oei era of the early Muromachi period (1394–1427) was an age of stable authority for the Ashikaga shogunal house and flourishing courtly and military culture in Kyoto. During this time, in Bizen Osafune (present-day Setouchi City, Okayama Prefecture), a group of sword smiths known as "Oei Bizen" was active, inheriting the great traditions of the Bizen school that began with Mitsutsuna, Nagatoki, and Kageyoshi of the Kamakura period, now carried forward in Muromachi style.

The twin peaks representing Oei Bizen are Morimitsu and Yasumitsu. These two were contemporaries, and since they left many works similar in style, the two are sometimes confused in questions of authenticity. However, skilled appraisers clearly distinguish between them based on fine details of the blade pattern, the texture of the metal, and the style of the signature.

Morimitsu's Forging Style—The Essence of Oei Bizen

Steel Surface (Jigane): Morimitsu's steel surface is based on the orthodox Bizen tradition of "tightly-packed small plate grain," characterized by lustrous, bright steel color. As the epitome of "Bizen skin," it is frequently cited by later appraisers as a teaching example. The "reflection" (utsuri) appears clearly, creating a white, burnished shadow along the blade pattern that enhances the beauty of the entire sword.

Blade Pattern (Hamon): The irregular blade pattern with clove-form motifs (choji) is Morimitsu's greatest distinguishing feature, reviving the clove aesthetic perfected by Kamakura Bizen smiths Kageyoshi and Motoshige during the Oei era. Morimitsu's clovers have rounded heads and are larger in size, sometimes intermingling with gunome patterns. The entire blade pattern maintains orderly regularity without becoming monotonous—this balance is the core of Morimitsu blade appeal. The scent-line (nioiguchi) is bright and clear, with fine, evenly distributed granules.

Shape and Form (Sugata): The Oei era coincided with the stable period of the Muromachi shogunate, so the grand and imposing long swords of the Nanboku-Cho period faded into the background, replaced by more practical and refined-sized long swords and katanas. Morimitsu's blades display excellent balance between width and depth, with graceful, beautifully-curved hip sections common. The point is modest, ranging from boar-neck to medium-point, creating a reserved impression that enhances overall harmony.

Signature (Mei): Morimitsu's typical signature reads "Bishu Osafune Morimitsu," and some surviving works include dates of creation (nenki). The signature is written in powerful, regular script with characteristic personal touches in the writing of the "mitsu" character—an important clue for identifying signatures. Since spurious signatures circulate, comprehensive judgment of the blade pattern and steel surface, not just the signature, is essential.

Representative Works and Surviving Examples

Multiple works by Morimitsu are designated as Important Cultural Properties or Important Art Objects, housed in the following institutions:

• Tokyo National Museum (multiple swords designated as Important Cultural Properties)
• Touken Museum (operated by the Japanese Art Sword Preservation Society)
• Various shrines and temples throughout Japan (dedicated to Atsuta Shrine, Sumiyoshi Taisha, and others)

Notable examples include long swords with Oei-era dates bearing clove-form irregular patterns, full length, and signed "Bishu Osafune Morimitsu," housed in several museums. Each is evaluated as the "apex of Oei Bizen," fusing the grandeur of Kamakura Bizen with the refined elegance of Muromachi.

Comparison with Yasumitsu—The Twin Peaks of Oei Bizen

Comparison between Morimitsu and Yasumitsu, his contemporary representing Oei Bizen, remains a constant topic of discussion among collectors and scholars.

Characteristics of Morimitsu: Clovers are large with rounded heads, displaying rich movement throughout. The slight darkness in the steel and clarity of the reflection epitomize Morimitsu's work.

Characteristics of Yasumitsu: Clovers are finely detailed and orderly, with particularly bright scent-lines. The steel appears somewhat brighter than Morimitsu's.

The difference is often summarized as "Morimitsu's richness versus Yasumitsu's refinement." Which ranks higher depends on personal preference and context, but both are equally represented among National Treasures and Important Cultural Properties, and their influence and evaluation are equally worthy of the title "twin peaks."

Stylistic Changes in Japanese Swords from the Perspective of Oei Bizen

The Oei era was a bridge period between "Kamakura's legacy" and "Muromachi's new style." Morimitsu's swords most vividly embody this transition, serving as "living proof" that the clove-form pattern tradition beginning with Mitsutsuna and Kageyoshi of Kamakura Bizen continued to thrive in Muromachi—making them crucial material for research in Japanese sword history.

One reason Bizen Osafune maintained nearly 1,000 years of history lies in how "bridge smiths" like Morimitsu and Yasumitsu inherited their region's technical traditions while responding to new demand in each era. Understanding the twin peaks of Oei Bizen is also understanding how the Bizen brand maintained value across centuries.

The Value of Oei-Era Swords—The Significance of Dated Works

Among Morimitsu's works, long swords and short swords bearing year marks from the Oei era carry particular weight in appraisal, as their creation date is certain—and command higher market valuations. Dated examples provide empirical documentation of the level of completion achieved by Bizen Osafune techniques during early Muromachi.

Surviving dated works by Morimitsu encompass both early and late Oei periods (1394–1427), revealing stylistic evolution—the early work showing strong remnants of Kamakura style, the later works displaying increased Muromachi refinement. This transition provides crucial reference points for periodizing "Oei Bizen" research.

Bizen Osafune's 1,000 Years and Morimitsu's Position

Bizen Osafune, a sword-making center since the Nara period, functioned as the heart of Japanese sword production for approximately 1,000 years through the Kamakura, Nanboku-Cho, Muromachi, Sengoku, and Edo periods. Within this vast history, Morimitsu occupies a special position as "the smith who bridged Kamakura's golden age to Muromachi."

Kageyoshi and Motoshige of the late Kamakura period had perfected the subtle clove-form patterns—the delicate aesthetics of Bizen that once retreated before the bold, all-hardened styles of the Nanboku-Cho period—and Morimitsu brilliantly revived them in the Oei era. This is why "Oei Bizen is the revival of Kamakura Bizen," and it is part of the reason the Bizen tradition continues to be cherished across generations.