Flying Trident (said to Have Been Owned by Kobo Daishi)

The Vajra That, by Legend, Flew Across the Sea

A vajra is a small ritual implement, no longer than a hand, that priests of esoteric Buddhism grip during prayer. Cast in metal with prongs at each end, it descends from an ancient Indian weapon and stands for the shattering of worldly desire. The example held on Mount Kōya is a three-pronged vajra, a sankosho, and it carries a name no other implement shares: the Flying Vajra, the Hikō Sankosho.

The name comes from one of the founding legends of Japanese Buddhism. According to the tradition, the monk Kūkai, later honored as Kōbō Daishi, finished his studies in Tang China and prepared to sail home in 806. From the harbor at Mingzhou, on the coast near present-day Ningbo, he is said to have hurled this vajra into the eastern sky with a prayer: let it come to rest where the new teaching should take root. The implement, the story goes, flew across the sea toward Japan.

The Pine That Caught It

Years later, the tradition continues, Kūkai searched the mountains for a site to found his monastery. Guided through the forest, he came at last to a high plateau ringed by peaks, and there, caught in the branches of a pine, he found the very vajra he had thrown from the Chinese shore. He took this as the sign he had prayed for and chose the spot for what became Kōyasan, the headquarters of Shingon Buddhism.

The pine is remembered as the Sanko-no-matsu, the Three-Pronged Pine, and a tree by that name still stands near the central precinct. Its needles, unusually, grow in clusters of three rather than the customary two, echoing the three prongs of the vajra; visitors hunt among the fallen needles for a three-needled sprig to carry home as a charm. The implement itself took the name Flying Vajra from this moment in the story.

None of this can be verified, and it should be read as sacred legend rather than history. The object is real, however, and old. Scholars place its manufacture in the Heian period, the era of Kūkai and the generations that followed him.

A Treasure That Left and Came Back

The vajra's recorded history is itself eventful. By tradition it passed from Kūkai to his disciple Shinzen and was later enshrined in the Miedō, the hall dedicated to the founder. In 1088 the retired emperor Shirakawa is said to have taken it from the mountain, and for more than a century it remained outside Kōyasan. It returned in 1253, and it has stayed among the treasures of the mountain ever since.

The implement was recognized as an Important Cultural Property in December 1897, in the very first round of designations under Japan's early heritage law. That early date reflects how central this object had become, not only as a ritual tool but as a tangible link to the figure who shaped Japanese esoteric Buddhism. For a tradition that prizes direct transmission from master to disciple, an implement believed to have passed through Kūkai's own hands carries a weight that goes beyond its small size.

What to Look For

The Flying Vajra is held by Kongōbu-ji and kept at the Reihōkan, the treasure museum on Mount Kōya. It is shown only rarely, so a traveler hoping to see the original should check the museum's special-exhibition schedule before making the trip rather than expecting it on permanent view.

When it is not on display, the legend is still everywhere on the mountain. The Sanko-no-matsu near the Danjō Garan complex lets you stand beneath a living descendant of the pine in the story and look for the three-needled clusters. Replicas of three-pronged vajras appear throughout the precinct, and priests still grasp such implements during the fire rituals that remain central to Shingon practice. To understand the small bronze object behind glass, it helps to see how the gesture it represents continues, unbroken, in the halls around it.