Zenkoji Temple Main Hall

A Hall Built the Wrong Way Round

The Zenkoji Temple Main Hall (善光寺本堂, known as Zenkoji Hondo and also written Zenkō-ji Hondō), the main hall of Zenkoji Temple in Nagano City, Nagano Prefecture, was completed in 1707 and designated a National Treasure on 31 March 1953. It had already been listed as an Important Cultural Property on 23 April 1908, making it one of the earliest buildings in Nagano to receive national protection.

Walk up the flagstone approach and the hall does not read the way a Japanese temple usually reads. Most Buddhist halls present a wide face and a shallow body. This one turns the proportion inside out. The Agency for Cultural Affairs records its dimensions in the old carpenter's units: fourteen ken along the flank, five ken across the front. The temple gives the modern figures as roughly 24 metres wide, 54 metres deep and 27 metres tall, which makes it among the largest wooden National Treasures in eastern Japan. You enter through the narrow end and keep walking.

The reason lies in the fire of 1700, which destroyed the previous hall, and in the reconstruction that followed. Fundraising fell to the temple administrator Keiun, who gathered donations from believers across the country. The design came from Kōra Buzen Nyūdō Sōga, a master carpenter attached to the Tokugawa shogunate, with his pupil Kimura Manbei serving as site foreman. Work finished in the seventh month of 1707. The rebuilt hall was set further back than its predecessor, which is why the modern precinct has the long ceremonial approach it does.

The roof gives the building its nickname. Seen from above, the ridge forms a T. That shape resembles a shumoku, the wooden mallet used to strike a temple bell, so the form is called shumoku-zukuri. The whole surface is laid in hiwadabuki, overlapping strips of cypress bark, a technique that requires bark harvested from living trees and re-laid roughly every four decades.

Why the Designation Came

The Agency for Cultural Affairs commentary is blunt about what makes the building matter: the plan is an outlier, and a deliberate one.

Japanese Buddhist halls grew from a core called the moya, normally 2 ken deep, occasionally 3 ken, wrapped by aisles. Builders could stretch such a hall lengthwise, as at Sanjūsangendō in Kyoto, the hall of 33 ken, but they could not easily deepen it. Medieval carpenters worked around the limit by setting two roofed structures back to back, producing the narabidō or raidō-zukuri arrangement that eventually settled into the squarish esoteric-sect halls of the Kamakura period.

Zenkoji's hall ignores that lineage. One reading holds that the deep interior was a response to Edo-period mass pilgrimage, since a popular temple needed room for crowds. The Agency's own commentary pushes back on this. Illustrated scrolls of the Zenkoji Nyorai legend show a markedly elongated hall in place well before the Edo period, which suggests the plan was already fixed by custom rather than invented for eighteenth-century visitors.

The elevation is as considered as the plan. Every column is round. The inner columns run high and carry a triple-stepped bracket complex (mitesaki) supporting the eaves, while the outer columns stop lower and carry a simpler degumi bracket beneath a skirt roof, or mokoshi. A gabled canopy with a curved karahafu gable projects 3 ken over the front entrance, with 1-ken canopies on each flank. Panelled doors open at the centre 5 ken of the facade, three at the rear, and two positions on each side; almost everything else is latticed window. A miniature shrine (zushi) is registered as an attached property of the designation.

Above your head the treatment changes by zone. The outer perimeter, 1 ken wide, shows exposed rafters finished as keshō yaneura. The outer worship space carries a coffered ceiling, and the inner sanctuary and middle sanctuary both step up to raised coffered ceilings.

What to Look For Inside

The interior divides into zones you pass through in sequence. The gejin, or outer sanctuary, begins as bare boards and becomes tatami further in. Beyond a 5-ken screen of doors lies the chūjin, 3 ken of tatami. Past that sits the 3-ken naijin, and at the very back the nainaijin with the Ruridan altar.

The principal image, an Ikkō Sanzon Amida Nyorai, has been an absolute hidden buddha since 654. Nobody sees it, including the abbots. A substitute image known as the maedachi honzon, itself an Important Cultural Property from the Kamakura period, is shown once every seven counted years at the Gokaichō. The next falls in 2027, running 77 days from 4 April to 19 June, with a ten-metre ekōbashira pillar raised in front of the hall and linked to the substitute image by a white cord. That pillar has come from Matsushiro for more than three centuries, a custom dating to 1707 when the Matsushiro domain supervised construction of this very building.

Also enshrined in the inner sanctuary are Yoshimitsu Honda, his wife and their son Yoshisuke, the family credited with founding the temple. Seeing an image of a founder placed alongside the main object of worship is unusual.

Under the Ruridan altar runs the feature most visitors remember. The okaidan-meguri is a passage beneath the floor, entered from the inner sanctuary, and it is genuinely dark. Not dim. You cannot see your own hand. Keep your right palm on the wall, shuffle forward, and somewhere near the midpoint your fingers meet a metal fitting called the Lock of Paradise, positioned directly below the hidden image. Touching it is said to establish a bond with the buddha. The circuit takes about five minutes and feels longer.

In the outer sanctuary, look for the seated Binzuru figure, worn smooth by generations of hands, and glance up at the transom carvings of the twenty-five bodhisattvas of the welcoming descent. The hemp curtains hanging in the hall carry a hollyhock crest, the family emblem of the Honda house.

Visiting the Zenkoji Temple Main Hall

Anyone may walk into the outer sanctuary of the Zenkoji Temple Main Hall. On its bare boards you can stand close to the worn statue of Binzuru and the raised tsumado-dai platform, said to recall the dance-chanting performed here in the Kamakura period. To step up onto the tatami of the inner sanctuary and make the okaidan meguri, you need the Main Hall inner sanctuary ticket, sold at a machine to the right as you enter from the front and at the amulet counters inside and just outside. Prices and opening hours for the whole temple are gathered on the Zenkoji Temple page.

The inner sanctuary is roughly 150 tatami mats in area. Ahead lies the innermost sanctuary; overhead, on the transom separating the two, the twenty-five bodhisattvas of Amida's welcoming procession glitter in relief. The okaidan meguri is genuinely pitch dark and narrow, so anyone uneasy in such spaces should not feel obliged to go down.

From the flagstones in front you only ever see the narrow end. Walk round to the east or west side and the 54-metre depth finally registers. The T-shaped ridge is hard to read from the ground, but from the upper gallery of the Sanmon Gate the great roof of the hall fills the view to the north.

Zenkoji says that photography and the use of images within the precinct and its buildings require an application. Keep the camera away inside the hall, and clear any pictures intended for news or publication with the temple office. If you can choose your time, come early. Around the morning service there are fewer people than at midday, and low sun catches the cypress-bark roof.