Kujaku-mon Kei: The Sacred Sound of Peacocks — A National Treasure at Chūson-ji Temple

Deep within the treasure hall of Chūson-ji Temple in Hiraizumi, Iwate Prefecture, a gilt-bronze gong has been quietly preserving the memory of medieval Japan for over 770 years. The Kujaku-mon Kei (孔雀文磬), or "Peacock-Design Ritual Gong," is one of Japan's most remarkable National Treasures in the metalwork category — a rare surviving Buddhist ceremonial instrument whose elegant form, intricate peacock ornamentation, and inscribed historical record offer a tangible link to the golden age of the Ōshū Fujiwara clan and the spiritual world of Kamakura-period Buddhism.

What Is a Kei? — The Voice of Buddhist Ceremony

A kei (磬) is a flat, mountain-shaped metal chime used in Buddhist temple rituals across Japan. Suspended from a special stand called a keika (磬架) by silken cords, the kei is positioned at the right side of the officiating priest and struck with a small wooden mallet during the recitation of sutras. Its clear, high-pitched resonance marks transitions within the ceremony — the beginning and end of chants, the titles of sacred texts, and other important moments in the liturgical flow.

The instrument traces its origins to ancient China, where stone chimes called qing (磬) were used as far back as the Shang dynasty. As Buddhism spread eastward, the chime was adapted into a ritual implement, eventually arriving in Japan along with Buddhist teachings. While Chinese originals were typically carved from jade or resonant stone, Japanese kei evolved into cast bronze forms with gilded surfaces. From the late Heian period onward, a standard decorative vocabulary emerged: a central lotus-shaped striking area (tsukiza) flanked by paired peacocks — a motif that gives this particular National Treasure its name.

The National Treasure: Kujaku-mon Kei of Chūson-ji

The Kujaku-mon Kei held at Chūson-ji's sub-temple Jizōin is a large and stately example of the form, weighing approximately 2.1 kilograms and measuring 32.4 centimeters across the shoulders. It was cast in bronze and gilded during the Kamakura period, and bears inscriptions on both faces that precisely document its origin: it was donated to the Senjudō (Thousand-Armed Kannon Hall) of Mōtsūji Temple in Kenchō 2 — the year 1250.

The front inscription reads: "Donated to the Senjudō of Mōtsūji, Kenchō 2." The reverse includes the same text with the addition of "First Month." This dual inscription confirms not only the date but the original home of this sacred object — Mōtsūji, the magnificent sister temple of Chūson-ji, located barely a kilometer away in the same World Heritage town of Hiraizumi.

At the center of the gong, a large lotus-blossom striking point is rendered in bold relief. Flanking it on both sides are a pair of peacocks, each holding a flower delicately in its beak and facing inward toward the lotus. The design is executed in the heraoshi (篦押し) technique — a method where the pattern is pressed into the mold before casting, resulting in a relief that is both refined and enduring.

Why It Was Designated a National Treasure

The Kujaku-mon Kei was first registered as an Important Cultural Property in 1929 and was elevated to National Treasure status on March 31, 1953. Several factors contributed to this distinguished designation.

First, the gong possesses a grand and majestic form. Its proportions are imposing yet harmonious — the nearly equal shoulder and hem widths, the low mountain profile, and the thick, substantial rim all convey a sense of solemnity and weight befitting a sacred object. Art historians describe the piece as exhibiting an overall archaic elegance while incorporating specific Kamakura-period characteristics, such as the nearly vertical side edges and the slight compression of the end arcs.

Second, the decorative execution is exceptional. The lotus striking point and the paired peacock motifs are cast with meticulous detail and described in official documentation as "dignified and graceful." The peacocks, symbols of both auspiciousness and spiritual power in Buddhist iconography, are rendered with a sophistication that reflects the highest metalworking standards of the era.

Third, the inscriptions provide invaluable historical documentation. With its date, place of dedication, and original temple clearly recorded, this kei serves as an important benchmark for scholars studying medieval Japanese Buddhist metalwork. It is one of only five kei gongs in all of Japan to hold National Treasure status, placing it in exceptionally rare company.

The Peacock in Buddhist Art

The choice of peacocks as the primary decorative motif is deeply rooted in Buddhist symbolism. In the Buddhist tradition, the peacock is believed to feed on poisonous snakes and toxic plants, yet it remains unharmed — a powerful metaphor for the enlightened mind's ability to transform suffering and impurity into wisdom. The peacock thus became a symbol of spiritual purification, protection, and the overcoming of obstacles.

The Peacock Wisdom King (Kujaku Myōō) is an important deity in esoteric Buddhism, closely associated with the removal of disasters and calamities. The presence of peacock imagery on a ritual gong used during sutra recitation carries layers of sacred meaning: the sound of the chime, combined with the visual power of the peacock motif, was believed to purify the ceremonial space and guide the hearts of practitioners toward awakening.

Hiraizumi and the Ōshū Fujiwara Clan

To fully appreciate this gong, one must understand the world that created it. Hiraizumi was the seat of the Ōshū Fujiwara clan, a powerful family that ruled northern Japan for roughly a century during the late Heian period (late 11th to late 12th century). Under their patronage, Hiraizumi became a cultural and spiritual center rivaling the imperial capital of Kyoto, with magnificent temples, Pure Land gardens, and an extraordinary concentration of Buddhist art.

Chūson-ji was founded in 850 by the revered monk Ennin (Jikaku Daishi) and later expanded dramatically by the first Fujiwara lord, Kiyohira, who began construction of its grand precinct in 1105. The dazzling Golden Hall (Konjikidō) — itself a National Treasure — was completed in 1124. Meanwhile, Mōtsūji Temple, about one kilometer to the south, was built by the second and third Fujiwara lords, Motohira and Hidehira, and became one of the most splendid temple complexes in all of Japan.

Although the Fujiwara clan was destroyed in 1189, and fires later consumed most of the original buildings, the treasures preserved at these sites continue to testify to the extraordinary civilization that flourished here. The Kujaku-mon Kei, dated 1250, was created during the Kamakura period — after the fall of the Fujiwara — but its dedication to the Senjudō at Mōtsūji demonstrates that the sacred traditions of these temples endured well beyond their founders.

Where to See It: The Sankōzō Treasure Hall

The Kujaku-mon Kei is displayed at the Sankōzō (讃衡蔵), Chūson-ji's on-site treasure hall, which houses over 3,000 items including multiple National Treasures and Important Cultural Properties. Inside the climate-controlled galleries, visitors can view the gong alongside other extraordinary works from the Fujiwara era, including the Raden Hakkaku Sumidan (mother-of-pearl octagonal altar platform), sutras copied in gold and silver ink on indigo paper, and ritual implements from the Golden Hall.

The Sankōzō is included in the combined admission ticket with the Golden Hall, making it easy to experience both highlights in a single visit. Note that photography is not permitted inside the treasure hall or the Golden Hall, so take your time to observe these masterpieces closely with your own eyes.

Exploring the Surroundings: A World Heritage Journey

Hiraizumi was inscribed as a UNESCO World Heritage Site in 2011 under the title "Hiraizumi — Temples, Gardens and Archaeological Sites Representing the Buddhist Pure Land." Five component assets make up the designation: Chūson-ji, Mōtsūji, the Kanjizaiōin ruins, the Muryōkōin ruins, and Mount Kinkeisan. Together they present a remarkably complete picture of how Pure Land Buddhist thought was translated into architecture, landscape, and art in medieval Japan.

A visit to Mōtsūji Temple is especially meaningful in the context of the Kujaku-mon Kei, since this gong was originally dedicated there. Today Mōtsūji is celebrated for its beautifully restored Pure Land garden, centered on the great Ōizumigaike pond. Though the original temple buildings have been lost to fire over the centuries, the garden survives as one of Japan's finest examples of Heian-period landscape design, holding the rare distinction of being both a Special Historic Site and a Special Place of Scenic Beauty.

The broader Hiraizumi area invites leisurely exploration. Takadachi Gikeido offers views over the Kitakami River from the spot traditionally associated with the tragic final stand of Minamoto no Yoshitsune. The Genbikei and Geibikei gorges in nearby Ichinoseki provide dramatic natural scenery, and the local cuisine — especially Hiraizumi's wanko soba and mochi-based dishes — adds another dimension to the journey.