Why are many streets in Tokyo’s western suburbs irregular rather than arranged in a grid?

In Tokyo’s western suburbs, the irregular street patterns exist because there is no overarching urban plan or grid system. Instead, the layout reflects the natural topography of the land, with streets wandering along ridges and valleys.1

This lack of order is often compared to the historical disorder of old paddy fields that once occupied the area. Furthermore, when roads encounter hilly terrain, they tend to deviate from a straight path to seek out detours, contributing to the confusing, non-linear nature of the suburbs. While some areas in the eastern part of the city feature a grid pattern, the western districts remain characterized by this organic, unplanned development.1