c) History of preservation/conservation

ii) Conservation work Throughout the long history of all three villages, the routine repair work on Historic Buildings such as the Gassho-style houses had been properly performed by the owners themselves or in some cases by the mutual labor exchange groups organized within the kumi. Since the time of designation as Important Preservation Districts or as Historic Sites, the work has continued to follow the traditional pattern but now receives support in the form of subsidies from the national, prefectural and local governments. Most of the conservation work involves rethatching work on all or part of the roof, but in some houses major conservation work with total or partial dismantlement has been necessary because of serious deterioration of the main structural frame. For this conservation work, an experienced conservation architect carries the responsibility for design and supervision of the work, thus assuring the historical authenticity of the construction. iii) Fire prevention work Thatched roofs are weak against fire, and in all three villages fire-extinguishing systems have been installed. In Ogimachi Village, 59 water jets equipped with fire hose apparatus and 62 additional independent fire hydrants were installed throughout the village. A 600-ton water reservoir was constructed in the hills above the village. With these systems in place, the whole village area can be protected, with all buildings within reach of the water spray. In Ainokura Village there are eleven fire hydrants and a system of water reservoirs and tanks with a total capacity of 405 tons, while Suganuma has four fire hydrants and water-storage tanks and reservoirs with a capacity of 140 tons. Thus these villages are also adequately protected against fire. Also, in each of the villages, fire-fighting squads composed of village residents have been organized, and periodical fire-fighting training exercises are carried out using the systems and equipment mentioned above. Appendix 5 : Maps showing changes in the distribution of Gassho-style houses in the Shirakawa-go / Gokayama area 5a: Map Indicating the Distribution in the Late 19th Century 5b: Map Indicating the Distribution in 1994 Appendix 7 : Plan indicating the buildings for which conservation work has been done since the time of designation 7a: Ogimachi Village 7b: Ainokura Village 7c: Suganuma Village Appendix 8 : Plan indicating locations of conservation management facilities and equipment: fire extinguishing systems 8a: Ogimachi Village 8b: Ainokura Village 8c: Suganuma Village Appendix 12 : Chronological table of conservation works 12a: Ogimachi Village 12b: Ainokura Village 12c: Suganuma Village Additional Reference Materials 10 : Report on the conservation work on the former Nakajima House in Suganuma Village