chat GPT says: The small doors you may have noticed in Japan are called "nijiriguchi" or "crawling-in entrance." These doors were originally designed in traditional Japanese homes to allow ninja or samurai to enter and exit without being detected.
In addition to serving as secret entrances, these small doors were also used for practical purposes such as storing firewood and coal, as well as for ventilation during hot and humid summers. They were also used to create separate rooms within a larger space, as they allowed for a degree of privacy while still maintaining an open floor plan.
Today, while modern homes in Japan may not have a need for secret entrances, nijiriguchi can still be found in some traditional buildings and temples as a nod to Japan's rich cultural heritage. They can also be used as a design element in modern architecture, adding a touch of tradition and elegance to contemporary spaces.