Iya-gawa) is the principal one, flowing from east to west and forming the entirety of the Iya Valley. Mount Tsurugi (剣山 Tsurugi-san), the second-highest peak on Shikoku island, is at the east end of the Iya Valley along the border with Tsurugi town, and from here the headwaters of the Iya River begin their flow from springs that come off the mountain, some of which are as high as 1800m. The Iya Valley follows this river for about 50 km, to the village of Iyaguchi (祖谷口) in Yamashiro District of Miyoshi City, where the Iya River joins the Yoshino River at an elevation of about 90m. The Iya Valley was formerly divided into two villages East Iya (東祖谷山村) and West Iya (西祖谷山村), however, on March 1, 2006, both villages merged with other local towns to form Miyoshi City. However the two former villages are still referred to by their old names locally, "Nishi-Iya" (West Iya) and "Higashi-Iya" (East Iya). The lower reaches of the Iya Valley are referred to as the Iya Gorge (祖谷渓 Iya-kei). This area is mostly undeveloped and unpopulated, but the original road that accesses the Iya Valley goes through here (Rt 32), which was built between 1902 and 1920. Though a more modern tunnel connecting the central valley to Oboke has been built (allowing faster and easier access to the main areas of the Iya Valley), it is still possible to enter by way of the old, mostly one-laned road through the gorge (called the "Iya Highway"). About halfway along this 20 km long cliffside, gorge road is the Peeing Boy Statue , which was installed in 1968 in honor of young boys who would traditionally relieve themselves from this high precipice. Culture As the valley has been historically isolated from the surrounding areas, it has developed its own unique heritage. Many of the traditions are still (just barely) alive, harking back to a time and style now largely lost elsewhere in Japan. Food Agriculture The traditional culinary offerings in the valley are based on what can be grown in the small terraced farm plots that climb up the hillsides through the valley's hamlets. Very few mechanized tools are used, though some people have small hand-pushed tilling machines. Nearly all crops are organically grown, with the main fertilizer being the susuki grass (also called kaya) that is also used for roof thatch. This grass is harvested