Unlike Western plazas, Japanese urban hirokōi, or “broad spaces,” are for passage rather than for gathering. Open public spaces on such a scale are unusual in Tokyo. This space, located at the hearth of Tokyo, introduces visitors to the imperial residence but, most importantly, has the function of evacuation point in case of great disasters.
Edo was one of the largest wood-built cities in the world and suffered many fires. Large public spaces started to be designed because of the demands of constant traffic and by the government’s insistence on creating a firebreak.