The Angle of a Kawara Tile Has Not Changed in 1400 Years

Kawara roof tiles come out of the kiln at exactly the same firing angle that Baekje-Korean potters brought to Japan with Buddhism in 588 CE. The angle is five degrees off horizontal. If it is set to four degrees the glaze does not carbonise properly; if it is set to six degrees the clay sags before the silica binds. The geometry was established in the early 7th century at Asuka-dera, the first Buddhist temple in the Japanese islands, and has held almost without modification for fourteen centuries. There are workshops on Awaji island today — grandfather-father-son operations, three generations running the same kilns — that produce kawara for the restoration of 8th-century temples using the 7th-century firing specifications, and the new tiles are physically indistinguishable from the original Nara-period tiles they are replacing.

Most traditional Japanese crafts have been disrupted by some combination of Meiji-era industrialisation, wartime material shortages, and post-war mass production. Kawara is an exception. It was heavily industrialised in the 1950s and 1960s, modern automated factories now produce about 80% of the volume, but the top-end artisanal production, the stuff that goes on temples and shrines and the roofs of prefectural-designated heritage buildings, has held the pre-industrial specifications. The two production systems run in parallel. The knowledge transfer between them is one of the more successful continuous-craft cases in modern Japan.

The Asuka Import

Roof tiles arrived in Japan on 14 March 588 CE along with a delegation of Baekje-Korean Buddhist artisans sent as a diplomatic gift from King Wideok of Baekje to the Soga clan of the Yamato court. The specific artisans on the manifest included four temple-architecture specialists, one bronze-statue caster, and two gawara-hakase (瓦博士, “roof-tile doctors”). The Nihon Shoki names two of the tile specialists: Mamutaku and Yoşisen. They had been sent specifically because the Soga, who were the aristocratic sponsors of the new Buddhist faith in Japan, were planning to build a major temple complex at Asuka-dera and had been informed by the Baekje court that temple roofs required tile rather than the thatch or plank construction the Japanese aristocracy had previously used.

Asuka-dera was completed in 596 CE. Its roof was tiled in classical Chinese-Korean hon-gawara two-piece format — a concave “female” (hira-gawara) and convex “male” (maru-gawara) alternating across the slope — using tiles that had been fired at a kiln the Baekje specialists established in the Asuka valley. The kiln site has been excavated (in 1956 and again in 1997) and the original production specifications reconstructed from the recovered tile fragments. The firing temperature was around 1,000°C; the clay mix was the volcanic tuff found in the surrounding Yamato basin; the final colour was a dark silver-grey from the ibushi smoke-reduction finish.

From Asuka-dera the technology spread outward. Hōryū-ji (completed 607, rebuilt after a 670 fire, standing since) used the same firing specifications. The Heijō-kyō capital construction at Nara in 710 used tiles produced at scaled-up versions of the Asuka kilns. By the end of the 8th century there were formal gawara-ha (tile-maker) guilds attached to every provincial government office in the country, and kawara had replaced thatch on most government buildings and most large temples.

The Three Regions

By the Edo period three regional production centres had consolidated most of Japan’s kawara industry between them. The consolidation was driven by clay quality: successful kawara production requires a clay with specific iron, silica, and particle-size properties, and only a few regional deposits in Japan have the right mix without extensive processing. The three regions that dominated, and still dominate, are Sanshū, Awaji, and Sekishū.

Sanshū kawara (三州瓦), from the Mikawa region around modern Takahama city in Aichi prefecture, is the current volume leader with about 60% of national production. Sanshū’s clay is a tuff-derived sedimentary mix excavated from the hills north-east of Takahama; the firing kilns there have been running continuously since the 14th century. The traditional Sanshū product is a dark-silver ibushi-finish san-gawara used on most mid-tier residential and commercial roofs east of Osaka.

Awaji kawara (淟路瓦), from Awaji Island in Hyogo prefecture, is the premium producer — about 25% of national volume but closer to 40% of high-end temple-roof work. Awaji’s clay is a volcanic deposit from the island’s own geology; the tiles have a slightly tighter grain than Sanshū and hold their finish longer in coastal salt-air conditions. Awaji is the region you go to if you want kawara for a shrine or a restored castle. Most of the recent Hōryū-ji and Osaka Castle roof restorations used Awaji tiles.

Sekishū kawara (石州瓦), from Masuda and Hamada cities in western Shimane prefecture, is the smallest of the three regions by volume (around 15%) and is known for frost resistance. Sekishū tiles are fired at a higher temperature (1,200°C versus the 1,000-1,050°C of Sanshū and Awaji) which vitrifies the silica content and makes the finished tile almost impervious to winter water absorption. This is why Sekishū kawara is standard on buildings north of Kyoto and across the Japan-Sea side of Honshū, where the typical winter involves forty to sixty freeze-thaw cycles that would shatter Sanshū tiles. The characteristic Sekishū colour is a reddish-orange glaze rather than the silver-grey ibushi of the other two regions.

How a Tile Is Made

A single kawara tile, made by traditional artisanal methods, goes through about two weeks of production. The process is:

Clay preparation (three days). Raw clay is excavated, screened to remove stones, mixed with water in open-air pits, and left to age. The ageing is essential; fresh clay contains organic matter that produces gas pockets during firing. Two to three days of ageing lets the organics oxidise and settles the particle distribution.

Forming (one day). The aged clay is pressed into a wooden mould specific to the tile type — hira-gawara (female), maru-gawara (male), or one of the decorative end-tiles. The mould work is done by hand even in modern factories; automation has not successfully replaced the skilled press-operator’s pressure judgement.

Drying (five to seven days). The formed tiles are set in a covered drying shed at ambient temperature for up to a week. The drying has to be slow and even or the tile will crack during subsequent firing. Humidity and temperature inside the drying shed are carefully monitored; rapid drying in hot weather produces surface hairline fractures that do not show until the tile is on a roof two years later.

Firing (two to three days). The dried tiles are loaded into a kiln, fired gradually up to the target temperature, held at temperature for 4 to 6 hours, and allowed to cool slowly. In traditional practice, a single kiln fires several hundred tiles per cycle. The firing is the part where the artisanal process has not yielded to automation — the slow temperature ramp, the exact hold time, and the cooling profile are specified by tile type and clay composition, and changing any of the three variables produces a measurable quality difference in the finished tile.

Smoke reduction (for ibushi finish only, four to six hours). The still-hot tiles, once the main firing is complete, are exposed to an oxygen-starved wood-smoke atmosphere inside the kiln. This produces the characteristic dark-silver metallic surface on Sanshū and Awaji kawara. Sekishū tiles skip this step and come out with the natural reddish-orange colour instead.

The full cycle produces a tile that can survive 100-150 years on a roof. A well-made Awaji ibushi hon-gawara on the north slope of a protected-exposure temple roof can reach 200 years. Several tiles from Hōryū-ji have been in service since the 1670s (the last major roof restoration there). The 8th-century tiles are long gone; those were replaced in the Genroku period. But the technology and the kiln that replaced them are indistinguishable, at the level of the individual tile, from the original.

Oni-gawara and the Decorative Tradition

The decorative kawara — the specialised ridge-end, corner, and eave tiles that ornament a traditional roof — are where kawara-making crosses over from industrial craft into sculpture. The generic term is kazari-gawara (飾瓦, “decorative tile”), and within the category the most famous subtype is the oni-gawara.

Oni-gawara production is a specialised branch of the craft. A skilled oni-shi (鬼師, “oni-master”) makes perhaps thirty to forty individual demon heads a year; each one is sculpted by hand from raw clay, fired in a separate small specialty kiln, and finished with the ibushi smoke reduction. The design is negotiated with the client, so that a temple’s oni-gawara will specifically reflect the temple’s iconographic preferences. Guild records from the 18th-century oni-shi association in Sanshū show annual output of about 800 demon heads per year across the whole region — which is roughly the current figure, three hundred years later.

Above the oni-gawara in hierarchy is the shachihoko — the tiger-headed fish that sits at the very top of a castle or palace roof. Shachihoko production is an even more specialised sub-speciality; there are fewer than a dozen living artisans in Japan certified to produce full-scale shachihoko for major castle restorations. The gold-leaf shachihoko pair on Nagoya Castle — each 2.7 metres long, each containing about 44 kg of cast bronze under the leaf — were last remade in 1959 after the original Edo-period set was destroyed in the 1945 bombing of Nagoya. The current pair is the work of a Sanshū-based shachihoko-shi named Makino Tadashi who spent three years on the commission.

The 20th-Century Industrialisation

The post-war reconstruction of Japan produced the first major disruption to the kawara industry in over a thousand years. From 1945 to 1965, roof-tile demand roughly tripled as an entire country rebuilt itself from bombing damage, and the traditional artisanal production system could not scale to meet it. Mechanised factories — using belt-driven forming presses, gas-fired tunnel kilns, and standardised clay-mix formulations — came into operation in Sanshū from about 1952 and dominated mid-tier roof-tile supply by 1965.

What kept the traditional kawara industry alive during this period was the temple and shrine restoration market. The mid-century restoration wave at major Japanese Buddhist sites — Tōdai-ji’s 1950s main-hall roofing, Hōryū-ji’s 1960s and 80s campaigns, the 1959 Nagoya Castle shachihoko remake — required tiles to specifications that the industrial factories could not match. Temple restoration committees insisted on hand-made hon-gawara fired in traditional kilns; the Awaji artisanal producers kept going on this market throughout the 1960s and 70s and have kept going since. The contemporary market structure — mass-produced industrial tiles on most modern construction, artisanal tiles on heritage restoration work — has been essentially stable for sixty years.

Several traditional kawara artisans have been designated Living National Treasures (ningen kokuho, 人間国宝) by the Japanese government since the system was established in 1955. The most recent designation was Ogasawara Takayuki, a Sekishū master artisan, in 2019. The designation carries a small annual stipend and an obligation to teach apprentices; most of the current generation of under-forty kawara artisans in Japan have trained under one of the designated masters.

Where to visit kawara country today

The kawara industry is geographically concentrated in the three regions described above. Two of the three have dedicated museums that are open to visitors and arrange factory tours.

1. Takahama Kawara Museum — Sanshū, Aichi

The Takahama Kawara Museum (高浜市やき物館, Takahama-shi Yakimono Hakubutsukan) is the Sanshū industry’s main visitor facility, in Takahama city about forty minutes by train from Nagoya. The museum combines a working kiln (open for demonstrations on weekends), a permanent exhibit on the 14th-century-onward history of the Sanshū industry, and an artisan-workshop wing where contemporary oni-shi and shachihoko-shi take student apprentices. Admission ¥500. If you are specifically interested in kawara, the museum arranges factory-tour visits to active Sanshū kilns on request; book two weeks ahead.

Access: Meitetsu Mikawa line to Takahama Minato Station, then ten-minute walk. Allow three hours for the museum plus tour if you are doing it. Best visited in autumn when the kiln smoke catches the low sun in a particular way.

2. Awaji Kawara-no-Sato — Minami-Awaji, Hyogo

Awaji Kawara-no-Sato (淟路瓦の郊) is the Awaji industry’s visitor centre, in Minami-Awaji city on the southern end of Awaji Island. The facility is adjacent to three active commercial kilns and runs regular guided tours of the kiln operations including hands-on forming demonstrations. The on-site gallery has the best single collection of contemporary Awaji-style kazari-gawara anywhere, and the gift shop sells small hand-sized kawara tiles (about ¥2,000) suitable for souvenir purposes. Admission to the gallery is free; kiln-tour bookings are ¥2,500 per person and should be arranged two weeks ahead.

Access: Awaji Island is reached by the Akashi-Kaikyo Bridge from Kobe (about forty minutes by bus) or by ferry from Osaka. Minami-Awaji is at the far southern end of the island; the full journey from Osaka is roughly two hours. Allow a half-day for the visit. Best combined with an overnight stay on Awaji Island to experience the island’s famously good seafood cuisine.

3. Sekishū Kawara Works — Masuda, Shimane

The Sekishū region has no centralised visitor facility but several of the larger traditional kilns in Masuda city accept pre-arranged visits. The most accessible is the Ogasawara-yaki kiln, owned by the 2019 Living National Treasure Ogasawara Takayuki, which runs English-language tours by appointment. Contact is through the Masuda city tourism office; bookings should be made a month ahead. Sekishū is remote, Masuda is two hours by train from Hiroshima, so the visit is only realistic if you are making a dedicated San’in-coast trip.

4. Kawara Museum — Ōmihachiman, Shiga

Ōmihachiman’s Kawara Museum (瓦の解説館, Kawara no Kaisetsu-kan) is not in a production region but is the best museum for understanding the full history and typology of kawara. The museum is small, an hour to walk through, but the exhibit design is the best in the category, and it is conveniently located in the traditional merchant district of Ōmihachiman which is a rewarding day-trip destination from Kyoto regardless. Admission ¥300.

Access: JR Biwako line to Ōmihachiman Station, then ten-minute walk into the old town. Combine with a visit to the Hō-kan-ji merchant museum and the Himure Hachiman shrine for a full half-day in the district.

Five Degrees Off

What makes kawara worth paying attention to, among the long list of Japanese traditional crafts, is the unusually good continuity. Most of the crafts that this site will cover — tatami, ranma, hakama, hibachi — have survived into the modern period with significant industrial compromises. Kawara has not compromised on the restoration-grade end of the market. The tiles you see on a properly maintained Japanese temple today, in 2025, are made to specifications set at Asuka-dera in the 590s and refined in a handful of workshop generations over the 1,440 years since. Other living craft traditions match that kind of continuity; very few exceed it.

If you are interested in the mechanical specifics — the five-degree firing angle, the slow cooling profile, the smoke-reduction chemistry — the Takahama museum has the most technical depth. If you want to see working kilns, Awaji Kawara-no-Sato is the better visit. If you want to see the tiles in situ on temple and shrine roofs, Tōdai-ji in Nara has the largest continuous area of traditional hon-gawara anywhere in Japan (5,200 square metres on the Great Buddha Hall alone), followed by Hōryū-ji and the Osaka Castle keep.

Go to Awaji if you can. Take the bus from Kobe across the Akashi-Kaikyo Bridge, the bridge itself is one of the world’s largest suspension bridges and worth the crossing for its own sake, and spend an afternoon at Kawara-no-Sato watching the kilns run. The kilns were designed in the 7th century. They are still going. The tiles that come out of them this week will be on roofs in 2175. Five degrees off horizontal, the angle of Mamutaku and Yoşisen, who sailed across the Korea Strait in March 588 to deliver a technology their Yamato customers had requested. The shipment arrived on time. The technology is still working.