The word kura means warehouse and these buildings were traditionally used for storage. Because the contents could be very valuable, kura were designed to be secure and the windows and doors look similar to the sort of vault door you might see in a bank. This was also to protect against fire and even though based on a wooden structure, the mud based walls would complete the physical barrier.
Typically they are built on a stone foundation and the structure simple rests on top of the stone.
This avoids significant damage during earthquakes and the tremendous weight and strength of the structure is sufficient that physical attachment to the foundation is not needed. The vast number of surviving kura, many over 200 years old, are in good condition, which is a testament to this design.
As kura were not designed to be habitable, the windows are usually small and ceilings might be low. In this case, the floor was dropped 30cm to give more headroom, and large windows were added, looking over the valley.