The key point here (and biggest advantage of Japanese cities) is that nearly every building is mixed-use by default, regardless of local density levels. This post does a great job illustrating the difference this makes:
https://urbankchoze.blogspot.com/2014/04/japanese-zoning.htm...
For comparison, even our best-case scenarios for urbanism here in the states (like NYC) have incredibly convoluted zoning rules, which in turn make it impossible to build anything new without intervention from the city/state:
https://zola.planninglabs.nyc/about#9.72/40.7125/-73.733
For comparison, even our best-case scenarios for urbanism here in the states (like NYC) have incredibly convoluted zoning rules, which in turn make it impossible to build anything new without intervention from the city/state: https://zola.planninglabs.nyc/about#9.72/40.7125/-73.733