• Kyodo News


Nippon Steel Corp. has started pitching a new product that could change the roofs of old traditional structures across the country, although the change may be almost unnoticeable to the untrained eye.

The nation’s biggest steelmaker has come up with a “kawara” roof tile made of titanium, while conventional kawara is ceramic made of dark gray clay.

Titanium kawara are much stronger and lighter than the old-style version, helping a structure stand up to a strong earthquake, the company says.

Pollution and the elements have left the kawara tiles of many old temples and shrines around the country in disrepair, and Nippon Steel says its kawara are also resistant to corrosion.

Sensoji Temple in Taito Ward, Tokyo, one of the most popular tourist spots for foreign visitors in the capital, has adopted the titanium product to cover the roof of its main hall.

“You can’t tell the difference in appearance when you look at them from a distance,” a temple employee says.

The temple first used titanium kawara to repair a temple gate in 2007 out of concern that the heavier conventional roof tiles could be shaken loose by an earthquake and injure visitors.

A titanium kawara measuring 20 cm by 22 cm weighs only 90 grams, 92 percent less than a conventional tile. The price is 2 1/2 to three times higher, but the titanium kawara’s superior durability means maintenance costs are a lot lower, Nippon Steel says.

Bending a titanium plate into the form of a kawara tile on a mass-production basis was once considered almost impossible because the metal is extremely hard and difficult to process.

Nippon Steel overcame that problem by using advanced processing technologies and relatively soft titanium plates produced by Kaname, a company based in Utsunomiya, Tochigi Prefecture.

“Now we expect demand to increase because we succeeded in processing (titanium) into the form of traditional kawara,” a Nippon Steel official says.

In a time of both misinformation and too much information, quality journalism is more crucial than ever.
By subscribing, you can help us get the story right.