Abstract
Ohdori Park is a favourite green mall in Sapporo City, which have developed from a broad boulevard proposed in gridiron town planning at the beginning of Meiji era. The boulevard assumed a dual role: firstly, as buffer zone between commoners' residence area and govermental office area including officials' residence, and secondly, as a fire preventive belt.
The author thinks that the above two concepts took over those of ruling class, that is, samurai class, appeared in urban design of castle towns in Edo era. Residence area of ruling class was alloted in the inner zone surrounding the main castle tower. On the other hand, the commoner class had to live over-crowded in the outer zone of town. The ruling class area was completely separated from the commoner class area by morts and banks. Therefore, They were protected from fires which frequently occured in densely built-up commoner area. In the case of castle towns like Kakunodate (Akita Pref.) and Ohno (Fukui Pref.), an open green belt with bank was provided for exclusively fire-preventive purpose.