In Part III, titled “City Planning and New Technology,” we discuss two topics, namely, compact cities and real estate technology in Japan.Promotion of compact cities is regarded as a high priority issue in urban policies in the era of population decrease. The Act on Special Measures concerning Urban Reconstruction in 2014 was revised to institutionalize the framework for the Location Normalization Plan, a plan for local governments to build compact cities to manage population decline and aging urban infrastructure while placing less burden on environment. Three chapters are devoted to issues related to this movement. In Chap. 10.1007/978-981-15-8848-8_18, Ishikawa (2020) discusses how urban functions can be guided by residents’ perspectives. To build a compact city, various day-to-day services must be placed proximal to residential areas; however, some services must be placed at a certain distance from residences because of land use restrictions. Therefore, we must determine the uses allowed in residential areas. In Chap. 10.1007/978-981-15-8848-8_19, Morimoto (2020) discusses the history of major contributions made by the development of transportation facilities to urban spread, the important role of traffic facilities to guide land use toward desirable purposes, and impact of self-driving vehicles on land use. In Chap. 10.1007/978-981-15-8848-8_20, Ogushi (2020) explains how the Location Normalization Plan in Niigata City was formed in detail.Real estate technology refers to real estate business-related services that use new technology. Several new services based on new technology have been introduced in the field of real estate in Japan. Three chapters are devoted to issues related to real estate technology. In Chap. 10.1007/978-981-15-8848-8_21, Narimoto (2020) explains the outline of real estate technology services in Japan and identifies legal problems associated with handling of information. In Chap. 10.1007/978-981-15-8848-8_22, Nishio and Ito (2020) report on creating a sky view factor calculating system that uses Google Street View. Sky view factor is a term that refers to a configuration factor for the amount of sky in a hypothetical hemisphere. In Chap. 10.1007/978-981-15-8848-8_23, Kiyota (2020) explains the transition of neural network research and characteristics of deep learning and introduces a system that detects category inconsistencies in real estate property photographs submitted by real estate companies by using deep learning and a system that detects indexes associated with ease of living based on property photographs.