It is said that the beauty of Japanese architecture consists in the variety of roof design. The roof is one of the most important elements in Japanese architecture both in function and expression. In wooden buildings, especially in Japan where we have rather heavy rains, it is not rational to make the roof flat, as is the case with reinforced concrete buildings.
As for roof forms used in Japanese architecture, there are several kinds such as the gabled roof, hipped roof, pyramidal roof and hipped roof with gables (irimoya). The last-named is a type of roof peculiar to Japan, and is quite foreign to Western architecture. The grand and imposing tiled roof of Buddhist temples, the light and solemn hiwada roof (covered with small thin pieces of hinoki) of Sinto shrines, the picturesque thatched roof of country houses, the elegant and tasteful roof of tea ceremony kiosks, the calm and subdued tiled roof of Japanese dwelling-houses, the magnificent and refined roof of old castles ; all bear witness to the wonderful beauty embodied in every variety of Japanese roofs.

THE FOUR FUNDAMENTAL FORMS OF JAPANESE ROOF DESIGN
A. Kirizuma (gable roof) B. Hogyo (square pyramidal roof) C. Sityu or Yosemune (hipped roof) D. Irimoya

There are many curved lines in the design of the Japanese roof, and the most remarkable are the curves of the eaves and the slope of the roof. The application of curved lines in Japanese architecture is based on a style imported from the Asiatic Continent, and dates from about the middle of the 6th century.

The prominent projection of eaves is another noteworthy characteristic of old Japanese buildings. This serves to increase the feeling of stability and to harmonize the form of the building. But this projection of the eaves is not for decoration only ; it was born of necessity. As summer in Japan is a season of rain, and the atmosphere then is very sultry, the people naturally like to open the windows to have good ventilation even during heavy rainfall.

Old dwelling house from “senzui byobu” series of screen pictures

“masu-gumi”

“Masu-gumi” (masu and hiziki) is a structural detail for supporting the overhanging eaves, and one of the most remarkable details of Japanese architecture. This device is one which is chosen to this day whenever an architect desires to obtain a pure Japanese effect. “ Masu-gumi ” was originally a part of the construction itself, though at the same time it adequately embodied a decorative effect.
It is an ingenious constructional detail which came originally from the Continent together with the introduction of Buddhistic architecture in the middle of the 6th century but in course of time it has come to be one of the most typical of Japanese architectural devices, as if it were an intrinsic symbol of Japanese Masu-gumi (masu and hiziki) architecture. Though many variations old form are found in “ Masu-gumi,” according to the different periods, the principle of structure is identical: first, projecting hiziki to the front or to the sides, then the placing of masu on the hiziki at varying distances, after which hiziki are projected on them, and the same process is repeated.

For this purpose, and also to prevent direct sunshine from penetrating into the room, the wide over-hanging eaves are indispensable. In winter, however, this projection of the eaves does not prevent the sunshine from entering and warming the room, as the sun travels low throughout the mainland of Japan during this season. This marked projection of the eaves often extends as much as 18 feet from the wall, as in some Buddhist temples ; and as heavy tiles are laid on it, it requires wise and solid devices of construction. The weight is skilfully balanced by the application of hanegi, the principle of which somewhat resembles that of a balance. Under the surface of the eaves, tarnki (rafters) are arranged in rows to counteract the monotony of the wide projecting eaves.

The Sinto shrine may well be considered the architectural symbol of ancient Japanese culture. The Sinto shrine is a building dedicated to Sintoism, the national religion of Japan, which, originating in Nature and ancestor worship and based upon a firm foundation, has prevailed since ancient times and has dominated the spiritual life of the Japanese nation. Even when Buddhism and Confucianism were introduced into Japan, Sintoism harmonized with them and it has come down to the present day. Many Sinto shrine buildings have been preserved unchanged in their original form through the ages.

There exist, at present, over 150,000 Sinto shrines in Japan. It may indeed be said that where one sees a a forest there one may find a sacred place entirely secluded from worldly life.

We find four principal forms of Sinto shrine building in ancient times: Taisya-zukuri (zitkun means architectural type), Otori-zukuri, Sumiyosi-zukuri and Sinmei- zukuri. Typical examples of these four types are : Izumo- Taisya (Taisya means great shrine), Otori-zinsya (.zinsya means Sinto shrine), Sumiyosi-zinsya and Ise-Daizingu (Daizingu means great shrine).

Ise-Daizingu (Uzi-Yamada, Mie Prefecture)

There are two shrines at Ise; one is the Geku (outer shrine) and the other the Naiku (inner shrine). These shrines are built on the same principle and in accordance with the same forms, representing a more developed stage in the art of Sinto shrine-building than the three types mentioned above. The sublime and solemn atmosphere of Sinto shrines pervades the whole precinct of the Ise Grand Shrine, and it is here that this atmosphere attains its highest expression. It is, so to speak, the symbol of Japan. Japanese spirit and taste will never fail to be recognized here.
Ise-Daizingu is the most sacred place in Japan. Spirit, nature and architecture are here united, and create a unique atmosphere which gives the visitor the impression of having been transported to the land of gods. The Ise-Daizingu is the highest embodiment of the Japanese spirit, and its architecture is the purest expression of original and genuine Japanese taste.

The original Sinto shrines such as the Ise-Daizingu, Izumo-Taisya and bumiyosi-zinsya were of pure Japanese style. But owing to the introduction of Buddhist arts, continental influences came to bear upon shrine building, so that new and compromised styles of shrine building developed during the 8th century. In the latter part of that century, there evolved such new styles of shrine building as the Kasuga-zukuri, Nagare-zukuri, Hatiman- zukuri and Hiyosi-zukuri. Typical examples of these new styles are the Kasuga-zinsya, Simogamo-zinsya, Usa-zingu and Hie-zinsya.

Kasuga-zinsya shrine, from "Kasuga-gonen reigen-ki" picture scroll …

Kasuga-zinsya (Kasugano, Nara)

No visitor to Nara will fail to go to this beautiful shrine, its rich vermilion colour contrasting with the green of the old trees of the surrounding forests. It was founded about the middle of the 8th century, but it took its present form of Kasuga-zukuri at the beginning of the Heian Period (784-1185). One of its architectural characteristics is the eaves (in Japanese kohai) which project over the front stairway and form a unique design in harmony with the front gable. The bright colours the wood, and the complex curves of the roof show the influence of continental styles.

It is needless to say that religion is often responsible for creating styles of architecture. Generally speaking, Japanese architecture has remarkable Buddhistic elements. This naturally comes from the fact that Japanese culture itself is based to a great extent on Buddhism.
It was in the 13th year of the Emperor Kinmei's reign (552 A.D.) that Buddhism was first introduced into Japan from Kudara, a part of Korea in those days. With the introduction of this religion, continental Buddhistic styles of architecture came to be eagerly copied, and greatly influenced the building art in Japan.
There are many sects in Buddhism, and those which were introduced into this country and which flourished in the Asuka and Nara Periods (552-783) were the so- called Nanto-Rikusyu (Six Sects of Nara): Sanron-syu, Kusya-syu, Hosso-syu, Zyozitu-syu, Kegon-syu and Ritu- syu. In the beginning of the Heian Period (784-1185), the two sects of Tendai and Singon were introduced from China. In the Kamakura Period (1186-1392), the Zen sect was introduced from the China of the Sung Dynasty ; while, on the other hand such sects as the Zyodo-syu, Sin-syu, Nitiren-syu, Zi-syu and Yuzunenbutu-syu were founded in Japan. In the Edo Period (1615-1867) the Obaku sect was introduced from the China of the Ming Dynasty.
Thus, since Buddhism was first brought over from the Continent, many different sects in succession have been introduced from China, while many new sects have been founded in Japan itself. Generally speaking, each successive government adopted a generous policy toward all these different sects of Buddhism, and thus each sect developed parallel to all the others. It is on account of this fact that we can fortunately see today typical Buddhist temple buildings in Japan which represent the development of each sect throughout the periods of her history. This is not so in China, where all sects except the Zen have perished.

Bird's eye view of Horyuji temple

This temple was completed in the 15th year of the Empress Suiko's reign (607 A.D.), and is one of the buildings of greatest historic value which remain in Japan today. It seems almost miraculous that the buildings of the Horyu-zi Temple should be more than 1,300 years old. The wood used there is a superior kind of htnoki, and the climate in that province is happily well suited for the preservation of wooden buildings. Moreover, the unvarying respect paid to this temple by the people has proved effective in making perfect preservation possible.

Nan-daimon of todaiji temple, nara

At the beginning of this period the Zen sect was introduced, and with this new sect a new building style was brought over from the China of the Sung Dynasty. We call it “ Kara-yo ” (kara means foreign and means style). The distinguishing features of the “ Kara-yo ” style are seen in the arrangement of the location of buildings : the principal buildings being arranged in a row on the central axis as in the Sitenno-zi style of the Asuka Period. The architectural and decorative treatment of the Kamakura Period shows a great change when compared with former styles. On the whole the effect is sombre and heavy. A good example of this style which now exists is the Syariden of the Engaku-zi Temple, Kamakura.
In this period, another style known as the “ Tenziku- yo,” a slight variation of the “ Kara-yo ” style, was developed. The Daibutu-den and Nan-dai-mon (great south gate) of the Todai-zi Temple, Nara, are specimens of this style, the remarkable features of which are to be observed in the details of “ Masu-gumi ” : masu and hiziki projecting only to the front and not to the sides..