Koryo (a moderately carved beam like a rainbow) of Daibutsu-den Hall (the Great Buddha hall) of Toda (東大寺大仏殿虹梁)

Two 23.5 meter-long beams of Japanese red pine are used to support the roof of Daibutsu-den Hall of Todai-ji Temple; these two beams were carried from the Shiratori Shrine of Hyuga Province (Ebino city) to Todai-ji Temple of Yamato Province by several hundred thousand people in 1704, and it took them nine months.

Process
Daibutsu-den Hall of Todai-ji Temple was burnt down during a war, in 1567 of the Sengoku period but in 1684, Kokei started Kanjin (temple solicitation) for the reconstruction of the hall. In 1686, they started collecting building materials and in leap month April 1688, they started the reconstruction. However, the material for Koryo, one of the most important parts, had not been found until that time.

Strong and highly durable Japanese red pines, each of which was 23.6 meter-long and the diameter of which was one meter-long, were necessary; Koryo of Daibutsu-den Hall of Todai-ji Temple were to be 23.1 meter, three times as long as the space between two pillars, which was 7,7 meters; the roof was to be 3020 tons. Kokei had searched various places for huge red pine trees that would meet the conditions mentioned above, but had not succeeded.

In 1702, Seiemon SONODA of Kobayashi, Hyuga Province (Kobayashi city), found two huge red pine trees in Shiratori Shrine, located on the side of Mt. Kirishima, and reported that news to Kokei through Satsuma Domain and Nara Bugyo. Kokei, on receiving that information, went to Shiratori Shrine to see whether those trees would meet the conditions. Kokei decided that the trees would be good materials for Koryo; the trees were 54-meter long, with no bendings or worm holes.

The logging operation by digging the ground
The trees might be spilt if they were cut down, so Kokei decided to log them by digging the ground around them. On September 19, 1703, they started the logging operation of the first tree. Ninety people were engaged in the operation, and the tree was logged on September 22. From 23 to 25 of September, 100 people worked for the logging operation of the second tree. Two Kyoryo materials were cut out of the trees and metal rings were applied to the ends of each tree, so that they would not be spilt even when they received shock. The first tree was 23.6-meter long, weighed 23.2 tons and the diameter of its butt was 1.3 meter and that of its tip end was 1.0 meter; the second tree was 23.6-meter long, weighed 20.4 tons and the diameter of its butt and tip end was 1.2-meter and 1.1-meter Suekuchi, respectively.

The transport of Koryo
They had to transport the timbers from Shiratori Shrine to the beach, which was hilly and 66 kilometers long. It is thought that they used a sleigh called Kinma and a guidepath called Sura; logs were placed like a drain in Sura. The transport started from Shiratori Shrine on January 7, 1704 and the timbers were carried to Shinkawaguchi (the mouth of Amori-gawa River) through Obeno (Ebino City), Kakutou (Ebino City), Yoshimatsu (Yusui-cho Town), Ushinoseto (Awano, Yusui-cho Town), Yokokawa (Kirishima City) and Torigoe (Kirishima City, Hayato). They had to go by several roundabout routes, and ended up walking 90 kilo meters. The Yamabugyo (a mountain magistrate) of Satsuma Domain directed a total of 100,000 people and they used 4,000 bulls for the transport; it took 115 days and they finally reached Shinkawaguchi on May 4.

The two timbers were made into a raft at Hamanoichi (Hayato port), adjacent to Shinkawaguchi, and pulled by six ships through Kagoshima Bay; it took three days to reach Kagoshimatsu (Kagoshima port). It was necessary to load the timbers on a ship because the raft was not strong enough to survive the choppy Hyuga-nada and Genkai-nada Seas, which they had to sail across on their way from Kagoshima to Kinai region. However,in those days they did not have the art of loading such huge timbers onto a ship and merchants were hesitant about the transportation.

Yagoro YAMASHITA, a merchant of Shibushi port, offered to transport them to Kinai region at the same charge as transporting rice; he said he had received an oracle from Kannon (Buddhist deity of mercy). Yagoro deliberately sank the ship in order to put the two huge timbers onto it. He sank the ship by opening the plug of the ship bottom on June 11 and placed the two timbers on the ship at full tide on June 12. He succeeded in loading the timbers by stoping the plug at low tide and bailing out water. It is said that the Kannon taught that method to Yagoro's daughter in her dream.

Kannonmaru, which carried the two timbers and 24 crew members, left Kagoshimatsu on June 20 and stopped over at Yamagawa port on June 21. The ship left the port at midnight of July 5, waiting for a south wind and reached Hyogotsu (Kobe port) on July 12. Yagoro used the same ship sinking method when he unloaded the timbers. The timbers were pulled by four ships from Hyogotsu and they arrived at the mouth of the Denpo-gawa River of Osaka (Osaka Prefecture) on July 16. Ships, with the timbers between them, sailed up the Yodo-gawa Riber and the Kizu-gawa River (Kyoto Prefecture). A total of 4,625 people were engaged in pulling the ship ashore from the riverbanks using ropes and the timbers arrived in Kizu (Kizugawa city) on August 10.

On August 19, each timber was loaded on two movable carriages in Kizu; they were pulled by workers to Todai-ji temple; they went up Ichisaka Hill (Kizugawa city) and Narazaka Hill (Nara city). A total of 17,000 people were engaged in pulling the timbers and tens of thounsands of people came to watch it.
The way how the timbers were transported was illustrated in 'Daibutsu-den Koryo Kobikizu (a picture of the transport of Koryo for Daibutsu-den).'
The first timber was carried into Todai-ji Temple on September 2 and the second timber on September 5.

After the transport
The timbers were placed into Daibutsu-den on March 13 and 18, 1705 and Jotoshiki (a framework raising ceremony) was held on April 10. The construction of Daibutsu-den was complete in 1709 and Rakkei hoyo (dedication ceremony) was held on March 21, that year; Koyo could not see it since he had passed away in 1705.

The renovation work, performed from 1905 to 1911, found 50 cm-bend in Koryo, which was reinforced by a steel beam.

The research of the Maehata Remains in Ebino city, Miyazaki Prefecture, conducted in 1979 for the construction of Kyushu Expressway, discovered ancient structural remnants considered to be a pathway where huge timbers seemed to have been dragged as well as ceramic ware pieces from the 16th century. The structural remnants were 1.8 to 2.0 meters in width and 50 meters in length from east to west, the full length of the excavation site; the remains were thought to be extending beyond the excavated area. There were some pockets with 10 to 20cm in depth and 20 to 40cm in width on the ground at gaps of 20 to 30cm; the pockets looked like marks of railroad ties. The researchers could not find out the purpose of the ancient structural remnants; however, recently it is considered, although there is no definite evidence in both cases, that the remains, as well as the similar remains discovered at the same time in Yamazaki Remains in Awano-cho town (Yusui-cho town), Kagoshima Prefecture, were used for transport of Koryo timbers in the past.