Short Sword〈Inscription/Chikushuju〉

Tantō Signed "Sa / Chikushū-jū" — A National Treasure Masterpiece by the Legendary Swordsmith Samonji

Among the most celebrated Japanese swords in existence, the tantō (short sword) bearing the inscription "Sa / Chikushū-jū" stands as a supreme achievement of the swordsmith's art. Forged during the Nanboku-chō period (14th century) by the master craftsman known as Sa — or more commonly, Samonji — this blade is designated a National Treasure of Japan. Also known by its historical epithet "Taikō Samonji" (太閤左文字) and the earlier name "Jyuraku" (聚楽), this short sword carries with it the legacies of some of Japan's most powerful historical figures, including Toyotomi Hideyoshi and Tokugawa Ieyasu. Today it is preserved at the Fukuyama Museum of Art in Hiroshima Prefecture, where visitors can witness firsthand the brilliance of medieval Japanese sword-making.

The Swordsmith Sa (Samonji): Revolutionizing the Kyūshū Sword Tradition

The creator of this tantō, known simply as "Sa" (左), was one of the most innovative swordsmiths of the Nanboku-chō era (1336–1392). Working in Hakata (modern-day Fukuoka City, Kyūshū), he inscribed his blades with the single character "左" — an abbreviation of his given name Saemon Saburō (左衛門三郎) — which led to his popular title "Samonji" (左文字, literally "the character Sa").

Before Sa's emergence, Kyūshū sword-making was characterized by a relatively austere style: coarse itame-hada grain with masame tendencies, and subdued straight hamon temper lines with cloudy nioiguchi. Sa utterly transformed this tradition. Drawing inspiration from the Sōshū (Sagami Province) school — he is traditionally counted among the legendary "Ten Great Students of Masamune" (Masamune Juttetsu) — Sa developed a radically new approach. His blades feature bright, refined jigane (steel surface), vivid chikei and kinsuji activity, and bold notare-based hamon with thick nie crystalline particles. His distinctive bōshi (temper pattern at the tip) — sharply pointed and sweeping upward with powerful energy — is virtually unmatched among swordsmiths of any province.

While Sa is known to have forged both tachi (long swords) and tantō, signed tachi are exceedingly rare. His only signed tachi designated as a National Treasure is the renowned Kōsetsu Samonji (江雪左文字), which is also held at the Fukuyama Museum of Art. It is as a tantō craftsman that Sa's genius reached its fullest expression, and the "Taikō Samonji" represents the finest example of his short-sword artistry.

Physical Characteristics and Artistic Merit

This tantō is forged in hira-zukuri (flat) construction with an iori-mune (ridged back). The blade is somewhat wider than typical for the period and carries a faint curvature. Its overall dimensions — a blade length (nagasa) of 23.6 cm and a tang length (nakago) of 8.8 cm — make it notably large among Sa's tantō works, most of which measure around 7 sun 5 bu (approximately 22.7 cm). At over 8 sun, this is the largest known signed tantō by the master.

The forging grain (kitae) is a finely packed ko-itame with touches of ayasugi-style large grain patterns, interspersed with chikei (dark lines in the steel surface) and thickly applied ji-nie (crystalline particles across the flat). The hamon is rendered primarily in notare (gentle undulating waves) mixed with small gunome (rounded zigzag patterns), broadening conspicuously from the middle toward the tip. Throughout the blade, vigorous sunagashi (swept sand-like lines) and kinsuji (golden streaks) appear, especially pronounced along the upper half — a hallmark of Sa's powerful style.

The bōshi features Sa's signature treatment: sweeping upward in a bold, pointed form with strong nie and emphatic hakikake (brush-sweep) effects at the tip. The tang is in its original, unaltered state (ubu nakago), taking a boat-like shape with a gentle curve and shallow blade-side kurijiri at the end. The file marks (yasurime) follow a large slanting pattern (ō-sujikai), and two mekugi-ana (peg holes) are present.

The accompanying habaki (blade collar) is a solid gold two-piece construction with the characters "長" and "左文字" engraved in fine hairline carving on the inner surface of the upper shell. The koshirae (mountings) are an aikuchi-style fitting with a lacquered scabbard decorated with paulownia crests over a gold ground.

Why This Tantō Was Designated a National Treasure

The tantō "Sa / Chikushū-jū" was first designated as an Old National Treasure (Kyū-Kokuhō) on January 30, 1934, under Japan's prewar preservation system. Following the enactment of the Law for the Protection of Cultural Properties in 1950, it was re-designated as a National Treasure (Shin-Kokuhō) on November 22, 1952.

The designation reflects several interrelated qualities. First, the blade is the largest known signed tantō by Sa and displays the full range of his technical and aesthetic achievements at their highest level — a balance of elegant form, brilliant steel, and dynamic hamon that no other work by this master quite matches. Second, the exceptional preservation allows modern viewers to appreciate virtually every aspect of the original workmanship. Third, the tantō's provenance — passing through the hands of Toyotomi Hideyoshi, Tokugawa Ieyasu, and Tokugawa Hidetada — provides irreplaceable historical significance. Finally, the blade exemplifies the revolutionary impact that Sa's Sōshū-influenced style had on the sword-making traditions of Kyūshū and, by extension, all of Japan.

Historical Provenance: From Hideyoshi to Fukuyama

The tantō's early history before it came into the possession of Toyotomi Hideyoshi's household remains unclear, but records indicate it was first held by Toyotomi Hidetsugu, Hideyoshi's nephew and adopted heir, who resided at the Jurakudai palace in Kyoto. How and when it passed from Hidetsugu to Hideyoshi himself is uncertain — Hidetsugu fell from favor in 1595 — but by Hideyoshi's later years the blade was firmly established as one of his personal treasures.

The tantō appears in the "Kōtoku Katana Ezu" (光徳刀絵図), a pictorial record of Hideyoshi's sword collection compiled by the renowned appraiser Hon'ami Kōtoku and copied by the metal artist Umetada Jyusai. In this document, the blade is annotated as "Shiyuraku" (志ゆらく), a phonetic rendering of "Jyuraku" (聚楽), referring to its connection with the Jurakudai.

In 1611, Toyotomi Hideyori — Hideyoshi's son and heir — met Tokugawa Ieyasu at Nijō Castle in Kyoto. As a diplomatic gift on that occasion, Hideyori presented this tantō along with the Nansen Ichimonji tachi to Ieyasu. The event is documented in the "Toyotomi-ke Okoshimono-chō" (豊臣家御腰物帳), a ledger of the Toyotomi family's sword collection.

Ieyasu passed the blade to his son Tokugawa Hidetada, the second shōgun, who is said to have carried it as his personal weapon (sashiryō). Hidetada later bestowed it upon Inoue Masanari, the daimyō of Hamamatsu in Tōtōmi Province (present-day Shizuoka Prefecture), whose family preserved it until the early Shōwa period. The blade subsequently passed through several noted collectors — including Nagao Yone and Aoyama Takayoshi — before becoming part of the Komatsu Yasuhiro Collection and eventually being donated to the city of Fukuyama in 2018 as part of a historic gift of fourteen swords, including seven National Treasures.

Highlights and What to Look For

When viewing this tantō at the Fukuyama Museum of Art, there are several features that reward careful observation. The jigane, or steel surface, displays a luminous quality with thick ji-nie shimmering across a tightly forged ko-itame grain — a stark departure from the comparatively dull steel typical of earlier Kyūshū swords. The interplay of chikei and kinsuji creates an effect sometimes described as "a galaxy within the steel."

The hamon along the cutting edge reveals the full drama of Sa's artistry. Gentle undulations of notare mix with small gunome, and dramatic sunagashi and kinsuji streak through the temper line like lightning, growing especially vigorous toward the tip. The bōshi is unmistakably Sa's — surging upward in a sharp, pointed sweep that contemporary scholars describe as brimming with "vigor and fighting spirit" (haki).

Finally, the nakago (tang) preserves Sa's distinctive mei (signature) — the single character "左" on the front and "筑州住" on the reverse — carved with a slender, energetic chisel stroke that specialists praise for its clarity and flow.

The Fukuyama Museum of Art and Its World-Class Sword Collection

The Fukuyama Museum of Art opened in 1988 within the grounds of Fukuyama Castle Park, creating a unique museum setting that blends modern architecture with historic surroundings. The museum's collection spans European modern art, Japanese paintings, and — since 2018 — one of the finest assemblages of National Treasure swords in Japan.

With the donation of the Komatsu Yasuhiro Collection, Fukuyama Museum of Art now holds seven National Treasure swords, tying with the Tokugawa Art Museum in Nagoya for the second-largest collection in the country, surpassed only by the Tokyo National Museum. The collection includes the Kōsetsu Samonji tachi, also forged by Sa, along with masterworks by Norifusa, Kunimitsu (Aizu Shintōgo), Masatsune, Kunimune, and Yoshifusa.

Please note that as National Treasure swords require careful conservation, not all pieces are on permanent display. Exhibition schedules rotate, and special exhibitions dedicated to the sword collection are held periodically. It is advisable to check the museum's official website or contact them directly before your visit to confirm which works are currently on view.

Nearby Attractions

A visit to the Fukuyama Museum of Art can easily be combined with exploration of the surrounding area. Fukuyama Castle, immediately adjacent to the museum, is one of the most conveniently located castles in Japan — its reconstructed tower stands just minutes from JR Fukuyama Station. The Hiroshima Prefectural Museum of History (Fukuyama Kusado Sengen Museum), a short walk south of the art museum, offers fascinating insights into medieval Japanese life through artifacts from the submerged Kusado Sengen town site.

For those with more time, the historic port town of Tomonoura (鞆の浦) lies approximately 30 minutes by bus from Fukuyama Station. This picturesque seaside village, with its Edo-period streetscapes and temples overlooking the Seto Inland Sea, has inspired filmmakers and artists for generations. Onomichi, another beloved town along the coast, is about 20 minutes by train and offers hillside temple walks and the famous Shimanami Kaido cycling route to Shikoku.