Due to the isolation of Japan for long periods of time, Japanese architecture is unique. China and Korea had an influence over Japanese architecture when it wasn't in isolation, but other than that buildings in Japan are very original. Japan’s architecture has not changed a lot over the years, and there are only small changes when looking at the timeline of Japan’s architecture. The Japanese used locally found materials such as timber, metal, clay, and fibre. Although stone was abundant in Japan, it was not commonly used unless it was used for building a defense mechanism such as a platform or a wall. Volcanic rock was used as fireproofing because the most destructive weapon used against a Japanese castle was fire. Stone was more commonly used in the gardens surrounding the castles. For example they were used as paving, steps, or natural boulders, which were a vital part of Japanese gardens. Timber was the main material in building castles. The Japanese painted and specially treated their wood. The timber was used to build the upper stories of castles. It was built in a log cabin style on top of a stone platform. The stone platform was common because the Japanese had to keep in mind the threat of natural disasters when building, and the stone platform helped. Japan’s castles are very unique because Japan was isolated and was prone to many natural disasters.