The Spiritual Meaning and Iconography of Blade Carvings (Horimono): How Dragons, Kurikara, Sanskrit, and Hi Grooves Express Faith and a Warrior's Prayer

"Prayers" Carved into the Blade

Carvings on a Japanese sword blade — called horimono — are not mere decoration. Most represent religious imagery from Buddhism, Shinto, and Daoism, embodying the beliefs and wishes of the samurai who wielded the blade. Whether carved by the swordsmith or a specialized carver (horiomonoshi) using chisels and small knives, these designs carry centuries of spiritual accumulation. This article examines the major images and their meanings from the perspective of intellectual history and iconography, while also addressing practical considerations important for appreciation and purchase.

Kurikara (the Dragon of Kurikara) — An Incarnation of Fudo Myoo

The most commonly seen carving on Japanese sword blades is "kurikara" — an image of a dragon wrapped around a sword, engulfed in flames. This imagery originates in Esoteric Buddhist devotion to Fudo Myoo (the Immovable One).

The Kurikara Dragon King (kurikara ryuuo) is an incarnation (samaya form) of Fudo Myoo, and the sword and flames symbolize his attributes (jimotsu) — the sword of wisdom that severs earthly desires and the flames that consume evil. The dragon embodies this power. When a samurai carved kurikara on the blade, it meant unifying the sword itself with Fudo Myoo's divine power. It was a declaration of faith: "This blade cuts the enemy by the will of Buddha."

Kurikara carvings appear from the Kamakura period and became widespread during the Nanboku-cho and Muromachi periods. The technique is especially evident in the depiction of coiling flames modeled on "homa fire" and in the intricate carving of the dragon's scales and claws. The depth of carving, line thickness, and the rendering of flame spirals show individual character by carver, and comparing different kurikara examples reveals stylistic variation — a pleasure of appreciation.

Bonji (Buddhist Characters) — The Script of Mantras and Guardian Deities

One or more bonji (Sanskrit characters) are often carved on sword blades. The most commonly used are:

• Ban (梵): Represents Dainichi Nyorai (the Great Sun Buddha), the supreme deity of Esoteric Buddhism and the embodiment of universal truth
• Kaan (劍): Represents Fudo Myoo. It has strong affinity with the blade and connects to the thought of regarding the sword itself as a homa stick
• A (阿): Represents the seed syllable of Dainichi Nyorai (Garbhadhatu realm), symbolizing the fundamental Buddha in Esoteric Buddhism
• Un (雲): May represent multiple buddhas including Bishamonten or Yakushi Nyorai

The Esoteric Buddhist philosophy that a single Sanskrit character contains an entire cosmology resonated with the aesthetic sense of samurai who sought to carve the universe into the small space of a sword blade. Bonji are not stylized decorative characters but require accurate letterforms and brushwork comparable to proper stroke order, demanding that carvers possess deep understanding of Buddhist iconography.

Grooves (Hi) — Where Function and Prayer Merge

The vertical grooves carved into the flat surface of the blade are called "hi." There are many varieties: round grooves (boubi), attached grooves (soehi), double grooves (futasujiihi), and flowing grooves (kakinagashi).

The functional role of hi is weight reduction while maintaining rigidity. Like the I-beam principle, grooves reduce weight while preserving strength without removing material. Additionally, when the blade is swung, air resistance in the groove creates a "whooshing" sound, said to have psychological impact in actual combat.

The hi also carries religious significance. In Zen Buddhism, "one sword, two sections" (ittou ryodan) — severing delusion with a single sword — serves as a metaphor for enlightenment. The form of the groove can be understood as a visual representation of this sense of "emptiness." Moreover, as the folk term "blood groove" indicates, the practical function of preventing blood from adhering to the blade became intertwined with folk belief, and meanings such as "expelling corrupted blood" were attributed. The width and termination point of the groove influence the overall impression of the blade's form, making evenness of carving and sharpness of the cut important points of appreciation.

The Union of Dragon and Sword — Symbols of Martial Power

When a dragon itself is carved (separately from kurikara), its meaning is based on dragon worship as "master of water" and "guardian of heaven." In East Asian mythology, the dragon symbolizes rain, water, abundance, and imperial authority. For samurai, it was imagery expressing the desire for protection by "one who embodies heaven's will."

The "sword-coiling dragon" (tsurugi maki ryuu), where a dragon coils around a sword, may be seen as a variant of kurikara, but when the connection to Fudo Myoo is not explicit, it is based on pure dragon deity worship. Historical records show that naval commanders who fought across seas and rivers favored such imagery. The composition can show the dragon ascending toward heaven or descending toward earth, and the precision in carving each individual scale, claw, and whisker reveals the carver's skill.

The Dove of Hachiman Daiboatsatsu — Kami of Japan and War

Dove carvings are rare but can be understood in relation to Hachiman Daiboatsatsu devotion. Hachiman is the guardian deity of samurai, and the dove is considered his messenger. When samurai made votive swords at Hachiman shrines to dedicate themselves to the protection of archery and swordsmanship, some bore doves carved into the blade.

Modern Carvers and the Continuity of Tradition

Modern sword carvers are extremely rare throughout Japan. Since carving is performed after polishing, a single mistake means the blade cannot realistically be repaired — work proceeds under this tension. Some modern sword smiths undertake carving themselves, but most outsource to specialized carvers.

Once you understand the meaning of traditional imagery, appreciating sword carvings reveals that blades are not merely weapons or craft objects, but function as "places where humans and the divine meet" — cultural artifacts shaped by centuries of belief. The Buddha's names, heavenly dragons, and divine messengers carved into the blade embody the very soul of the samurai who carried it. Understanding the origins and techniques of carving provides a reliable key to savoring each sword more deeply.

Distinguishing Authenticity in Carving — Original Carving and Later Carving

When appreciating or purchasing sword blade carvings, determining when the carving was executed becomes practically important. Carving planned from the initial forging of the blade and executed by the swordsmith himself or by a contemporary carver is called "raw carving" (ububori), while carving added later to an existing blade by a different craftsman is called "later carving" (atobori) — a distinction that matters. Raw carving has the blade's form, thickness, and groove placement designed as a unified whole with the carving composition, while later carving often shows unnaturalness in position and depth balance. Comparing the condition of the ground metal around the carving and the sharpness of the carved edges serves as guidance for appreciation and authentication.

For blades with maker's signatures (mei), it is important to verify whether the carving style aligns with the work of the swordsmith and period recorded in the signature. NBTHK (the Japan Art Sword and Blade Preservation Society) authentication certificates document the blade's form, ground metal, and hamon pattern, and the presence and style of carving may also be recorded. Before purchase, it is advisable to compare the certificate's recorded information with the actual carving on the blade.

Care and Storage Considerations for Blades with Carving

The grooves and carvings of bonji and dragons have more surface irregularity than the flat portions, making it easy for struck powder (uchiko) dust and old oil to accumulate in the grooves. During maintenance, it is desirable to wipe along the groove direction with a soft cloth, carefully reaching into the depths without missing areas. Since carved sections are harder to distribute oil evenly than flat surfaces, developing the habit of periodically checking for uneven oil application is important.

Regarding storage environment, as with all sword blades, place the blade in a sword bag in a location avoiding abrupt humidity changes, keep it in the saya, and store horizontally in a lying position. Since moisture tends to accumulate in the depths of carved sections, take care not to leave excessive intervals between maintenance and storage.