The Onin War and the Sword Industry: How the War Transformed Bizen and Mino Forging Systems and Sword Distribution
* Image is for illustrative purposes only.Table of Contents
The Ōnin War, which lasted from 1467 (Ōnin 1) to 1477 (Bunmei 9), left deep scars across Japan's politics, society, and culture. Its effects extended to the Japanese sword industry, fundamentally transforming the structure of sword production and distribution that preceded it. This article analyzes the Ōnin War as a "turning point in sword-making history," examining the rise and fall of two major production centers—Bizen (present-day Okayama Prefecture) and Mino (present-day Gifu Prefecture)—and the advent of mass-production via "kazuuchimono."
The Sword Industry Before the Ōnin War—Bizen Osafune's Dominance
Before the Ōnin War, Japan's sword industry could be described as being under "monopolistic control by Bizen Osafune." While sword makers certainly existed in Yamashiro, Yamato, Sōshū, and Mino, Bizen Osafune occupied an overwhelmingly dominant position in terms of production volume, quality, and distribution networks.
There were multiple reasons for Bizen Osafune's prosperity.
- It was close to high-quality iron sand deposits (the Chūgoku Mountains) and possessed abundant charcoal resources for metalworking
- An advanced distribution network had developed using the Osafune River and Yoshii River waterways, with a system in place to distribute completed swords nationwide via the Seto Inland Sea
- An established brand as a "famous sword production center" since the Ashikaga shogunate and Emperor Gotoba had created stable demand from the nobility, samurai class, and temples/shrines
In the decades just before the Ōnin War (the 1460s), Bizen Osafune was home to multiple workshops of sword makers descended from renowned masters of the Northern and Southern Courts period—such as Kagemitsu, Kanemitsu, Nagayoshi, and Motoshige—and their annual production is estimated to have met more than half of nationwide demand, including the Eastern Provinces.
The Impact of the Ōnin War—A Direct Blow to Bizen Osafune
When the Ōnin War began, Bizen Osafune suffered a double blow. The first blow was the "severing of distribution networks." Warfare disrupted transportation on the Sanyō Road and Seto Inland Sea waterways, making it difficult to transport Bizen swords to Kyoto and the Kinai region, their primary markets.
The second blow was a "sudden shift in demand." During peaceful times, sword demand centered on individual custom orders: "commissioning a single high-quality blade over several years." However, as warfare intensified, daimyo and regional lords sought "practical combat swords they could obtain in large quantities immediately." The intricate Bizen sword-making process—the formation of complex hamon through soil-bed tempering—was poorly suited to meeting this new demand.
Furthermore, conflict spread to Bizen itself, and the Osafune workshops themselves suffered damage. Historical records from the period confirm that Osafune sword makers temporarily scattered. In this chaos, some sword makers left Bizen and relocated to various domains under powerful daimyo. This "dispersal of sword makers" became the catalyst for techniques previously concentrated in Bizen to spread across the nation.
The Rise of Mino Swords—Meeting Practical Combat Demand
The sword industry of Mino (present-day Gifu Prefecture) rose rapidly after the Ōnin War as a turning point. The center of Mino was Seki, where a group of sword makers collectively known as "Seki smiths" lived in close quarters.
The reason Mino swords could meet Sengoku-period demand lay in their "rational production process." Rather than the refined chōji hamon of Bizen, Mino sword makers specialized in hamon based on practical patterns such as gunome and suguha. These could achieve stable quality in relatively short time periods and were suited to mass production.
Additionally, Mino was positioned at a "strategic junction of overland transportation." Mino Province lay at the intersection of the Tōkaidō, Nakasendō, and Hokuriku roads, giving the Seki-centered sword industry an advantage in distribution to both eastern and western regions. As Sengoku warfare made land-based logistics paramount, Mino held an advantage over Bizen, which relied on water transport.
From the post-Ōnin War period through the Sengoku era, the number of sword makers in Mino Seki increased dramatically. In particular, lineages such as "Kanemoto" and "Kanesada" established their reputation as "wazamono"—swords of exceptional cutting ability—and began receiving commissions from Sengoku warlords nationwide. Mino's "Magoroku Kanemoto" became one of the most widely used tachi during the Sengoku period, appearing repeatedly in military treatises and war chronicles.
The Establishment of Kazuuchimono Economics—The Separation of Mass Production and Quality
The decisive change that emerged in the post-Ōnin War sword market was the proliferation of "kazuuchimono." Kazuuchimono refers not to individual custom commissions but to swords mass-produced through standardized, regulated processes.
While Mino was the center of kazuuchimono production, Bizen also produced them. Though of lower quality than custom-commissioned blades (specially made individual orders), their prices were dramatically cheaper and could be procured in large quantities. When Sengoku daimyo needed to equip thousands to tens of thousands of troops, it was impossible to furnish each with a custom-made master blade. Kazuuchimono filled this demand.
The establishment of kazuuchimono economics created a "two-tiered" sword industry.
| Tier | Producer | Target/Characteristics |
|---|---|---|
| Upper | Custom-commissioned blades by master smiths | High-priced, high-quality products for daimyo and senior samurai |
| Lower | Mass-produced kazuuchimono by production-focused smiths and forges | Low-priced, standardized products for common foot soldiers and minor samurai families |
This two-tiered structure continued into the Edo period and beyond, becoming the distant prototype for the modern market structure of "Living National Treasure creations versus mass-produced iaido swords."
The Dispersal of Kyoto Sword Makers—The Acceleration of Technical Dissemination
The Ōnin War brought devastating damage to Kyoto as well, and the sword makers of Yamashiro (Kyoto) suffered major losses. Some Kyoto sword makers, from lineages such as Sanjō, Awataaguchi, and Rai, sought safety during the warfare and relocated to various regions.
This "dispersal of Kyoto sword makers" had the effect of spreading the high-level techniques previously concentrated in Kyoto throughout the nation. For example, genealogical records confirm that Rai-school techniques later influenced sword makers in remote regions such as Satsuma and Kii. While the regional dispersal of techniques meant short-term collapse of production centers, it contributed long-term to raising sword-making standards across all of Japan.
Conclusion—The New Order in the Sword Industry Created by the Ōnin War
The Ōnin War brought the following structural changes to the Japanese sword industry.
- Bizen Osafune's distribution dominance collapsed, and emerging production centers centered on Mino and Seki rose to prominence
- A mass-production system for kazuuchimono was established, and the sword market shifted from a "quality-focused market" to a "two-tiered market balancing quantity and quality"
- Geographic dispersal of sword makers advanced, and the nationwide dissemination of sword-making techniques accelerated
To understand Sengoku-era swords—from the anonymous kazuuchimono used by common foot soldiers to the custom-commissioned blades favored by powerful samurai—it is essential to understand this industrial structure created by the Ōnin War.
