We had the privelege of visiting the neighborhood of Mukojima in Sumida ward with some members of the local Machizukuri. We had attended a lecture on disaster planning and the pivotal role of fires in Tokyo planning history given by Nakai-sensei earlier in the day at Tokyo Institute of Technology, so we had fires on our mind.
Mukojima is a historic neighborhood which remains ordered by the historic Edo street pattern. It lies in the shadow of the newly completed Tokyo Sky Tree, and its historic pattern is vulnerable to new building and setback standards put forth by the city. Simply put, whenever a older style wooden house is demolished, the street is widened to meet the new standard.
This new layout is safer - the risk of fire is lower (due to Japan's extreme seismologic activity and history of disaster, fires in Tokyo are a constant concern) and emergency access is easier. However, these new layouts permanently alter the character of this historic neighborhood - a tradeoff that the machizukuri is trying to balance.
We also got a chance to see the neighborhoods pocket parks - former residential lots developed into public space - partially to serve as firebreaks.