Administered by the Agency for Cultural Affairs, various levels of historic preservation do exist. But midcentury buildings have yet to benefit in a big way. Treasured for their enduring beauty, cultural value and link to the past, traditional timber temples and teahouses or Meiji era (1868-1912) red brick edifices are regularly protected. By contrast, buildings made of glass, steel and concrete seldom stick around long enough to acquire a comparable patina. In 1996, the government extended the scope of its preservation program to 50-year-old buildings. However, this coverage is neither ironclad nor irretractable. Buildings can still be altered or delisted and then torn down. And the expense of refurbishing and maintaining these properties is borne mostly by owners.