Aoe Tsugunao

Aoe Tsugunao and the Bichū Aoe School

Aoe Tsugunao was a swordsmith who flourished during the Nanboku-chō period in Bichū province Aoe (present-day vicinity of Kurashiki, Okayama Prefecture) and is remembered in Japanese sword history as one of the representative figures of the Bichū Aoe school (late Aoe). The name "Tsugunao" (次直), with its character "tsu" (次) possibly indicating a generation, has been recorded in various authentication documents as a swordsmith occupying an important position within the genealogy of the Aoe school.

The Aoe school was a regional collective of swordsmiths that emerged around the Aoe village area of Bichū province in the late Heian period and reached its zenith during the mid-Kamakura period. While rooted in the same Bichū region, it possessed a distinctive aesthetic entirely separate from the neighboring Bizen province's Osafune and Ichimonji schools, and has been renowned since antiquity for the unique beauty of its steel called "aoe-hada" (青江肌).

Mid-Kamakura Bichū occupied a strategic position between Bizen and Yamashiro provinces and was known as a source of iron sand and charcoal. Against this backdrop of geographic and resource advantage, the Aoe school developed unique hamon techniques using distinctive iron, presenting a "quiet beauty" that set it apart from Bizen.

The Secret of Aoe-hada and Tsugunao's Technique

What stands out most prominently in the works of Aoe Tsugunao is precisely the beauty of the steel called "aoe-hada." The defining characteristic of this surface is a cool, clear bluish tone that permeates the entire steel—a phenomenon unique to Bichū, created through the interplay of trace elements within the iron and the processes of forging and heat-treatment.

The steel displays distinctive large-scale surface patterns with a flowing texture, in which rod-like formations (sumizumi-hada) appear in places. Unlike typical ko-itame-hada or masame patterns, this large hada creates an impression of flowing, undulating waves across the entire blade. Upon this sits an even covering of fine jigane, creating an otherworldly radiance through contrast with the bluish steel.

The hamon is characterized by straight lines and small irregularities, with reversed chōji (gyaku-chōji)—where the head inclines downward—interspersed throughout, a hallmark of the Aoe school. Whereas standard chōji points upward toward the edge, reversed chōji inclines downward toward the tang. This imparts a distinctive sense of gravity and stability to the hamon, expressing a "restrained beauty" in contrast to Bizen's ascending chōji forms.

Tsugunao's works also feature gunome and ko-gunome variations, avoiding monotony through deliberate change. The bōshi typically returns in straight fashion, maintaining the characteristic refinement of the Aoe school. The combination of bluish steel and reversed-chōji hamon embodies Aoe Tsugunao's unique artistry and serves as a decisive identifying feature in sword authentication.

Tsugunao and Contemporaneous Masters of the Aoe School

Beyond Tsugunao, the Aoe school produced many accomplished smiths including Tsunetsugu, Sadatsugu, Tsuguke, and Shigetsugu (Tsunetsugu and others represent the ancient Aoe of the Kamakura period, while Tsugunao represents the late Aoe of the Nanboku-chō period). Among them, Aoe Tsunetsugu of the ancient Aoe is known for the famous sword "Juzu-maru Tsunetsugu" (one of the Five Legendary Swords, designated Important Cultural Property) and stands as the emblematic figure of the Aoe school; however, Tsugunao of the Nanboku-chō period is equally evaluated as a master whose surviving works maintain equally high standards.

Many Aoe smiths bore the character "tsu" (次) in their names—Tsugunao, Tsunetsugu, Sadatsugu, Tsuguke—a naming convention possibly indicating genealogical or familial relationships within the school. Tsugunao, true to his name, likely served as "the inheritor of the next generation's directness," carrying forward the technical continuity of the Aoe school.

The Aoe smiths formed a major collective, competing technically with one another while united under the shared aesthetic of aoe-hada and reversed chōji. This collective technical foundation enabled individual smiths to produce consistently high-quality works.

Bichū Aoe and Geographic Influence

The Aoe village area of Bichū was blessed with iron sand rich in iron content flowing from the Kibi plateau and high-quality charcoal, creating an ideal environment for sword production. Particularly, the iron sand known as "Aoe sand iron" produced in Bichū contains distinctive minerals, and some scholars propose this as contributing to the bluish quality of aoe-hada steel.

Geographically, Bichū occupied the midpoint between Bizen and Yamashiro, serving as a conduit for cultural and technical exchange between east and west. That the region maintained its distinctive identity while influenced by Bizen's chōji-midare reflects a geographical tension and independent spirit born from Bichū's strategic position.

Tsugunao's Legacy and the Sword Pavilion

What Aoe Tsugunao's blades embody is the latter in the duality of beauty: "quiet restraint as opposed to brilliance"—"stability over ascension." If Bizen's chōji expresses the vitality of upward movement, Aoe's reversed chōji expresses stability and depth in submission to gravity. This contrast reflects not merely technical difference but the fundamental duality of Japanese aesthetics—movement and stillness, yang and yin.

The Sword Pavilion (Tōkenzan) aims to convey the breadth of Japanese sword beauty by introducing not only Aoe Tsunetsugu but the diverse masters of the Aoe school including Aoe Tsugunao. The clear bluish steel and the quietly descending reversed-chōji hamon—understanding this "beauty of Aoe" is to understand the profound artistry of the Japanese sword.