(outlined) of northern Greater Tokyo, 1960s to 2010. Notice how the densely populated zones grow along railway lines and stations, the purple circles and lines. Green southern border is Tokyo. There are various definitions of the Greater Tokyo Area, each of which tries to incorporate different aspects. Some definitions are clearly defined by law or government regulation, some are based coarsely on administrative areas, while others are for research purposes such as commuting patterns or distance from
Central Tokyo. Each definition has a different population figure, granularity, methodology, and spatial association.
Various definitions of Tokyo, Greater Tokyo, and Kantō Notes and sources: All figures issued by Japan Statistics Bureau, except for Metro Employment Area, a study by
Center for Spatial Information Service, the
University of Tokyo. Abbreviations: CF for National Census Final Data (every 5 years by JSB), CR for Civil Registry (compiled by local governments, monthly as per legal requirement), CP for Census Preliminary.
National Capital Region The of Japan refers to the Greater Tokyo Area as defined by the of 1956, which defines it as "Tokyo and its surrounding area declared by
government ordinance." The government ordinance defined it as Tokyo and all six prefectures in the Kantō region plus Yamanashi Prefecture. While this includes all of Greater Tokyo, it also includes sparsely populated mountain areas as well as the far-flung
Bonin Islands which are administered under Tokyo.
International comparison Using the "One Metropolis Three Prefectures" definition, Tokyo is , a similar size to that of
Los Angeles County, and almost two-thirds smaller than the
combined statistical area of
New York City, at and 21.9 million people. Other metropolitan areas such as
Greater Jakarta are considerably more compact as well as more densely populated than Greater Tokyo.
Metropolitan Area definition ambiguities and issues • The is a potentially ambiguous term. Informally, it may mean the One Metropolis, Two Prefectures, or the area without Saitama Prefecture. Formally, it may mean the South Kantō Block, which is not the Greater Tokyo Area, but a
proportional representation block of the national election, comprising Kanagawa, Chiba, and Yamanashi Prefectures. • In informal occasions, the term often means Greater Tokyo Area. Officially, the term refers to a much larger area, namely the whole Kantō region and Yamanashi Prefecture. • Tokyo as a metropolis includes some 394 km of islands (the
Izu and
Ogasawara islands), as well as some mountainous areas to the far west (331 km), which are officially part of Greater Tokyo, but are wilderness or rustic areas. ==Cities==