Irori Fireplaces
The irori fireplace is the warm heart of the gassho-style house. Besides being used for everyday chores such as preparing food and boiling water, the irori traditionally served a social purpose: Both the inhabitants of the house and guests would gather around it to eat, converse, and simply spend time with each other. Furthermore, gassho-style houses were built to benefit from the smoke and heat rising constantly from the fireplace and passing through the lattice ceiling into the attic. Over time, soot from the smoke sticks to every part of the house’s interior, coloring it black and improving the wood’s resistance to moisture and pests. The heat that reaches the attic helps keep the thatched roof dry, preventing rot and premature decay. The same heat contributes to keeping the temperature in the attic fairly constant, which was important when this part of the gassho-style house was used for sericulture, which flourished from the eighteenth century to the first few decades of the twentieth century. Lastly, the irori also supported another local industry: Holes were dug under the fireplaces to make saltpeter, an essential ingredient in gunpowder, the production of which involves a fermentation process that relies on a stable supply of heat.