The address is how it appears at the bottom of the organization’s website, www.nii.ac.jp :
国立情報学研究所 テ101-8430 東京都千代田区一ツ橋2－1－2
On English pages of the same site, for example, www.nii.ac.jp/en , it appears as:
National Institute for Informatics
2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430
Notes
The name of this organization has a well established English translation and acronym (NII). It is not always clear whether an organization prefers its long name or its acronym. Many/All of the divisions and other parts of the organization also have established English translations. What should the policy be when an organization name has no established English translation?
The rest of the address is transliterated using some form of Hepburn Romanization. Strictly speaking Tokyo should be Tōkyō. See here for further information: http://en.wikipedia.org/wiki/Hepburn_romanization
Japanese addresses are not normally translated. I shall translate this address to illustrate the point and for your amusement:
2-1-2 One Bridge, Thousand Generations Field Ward, East Capital Metropolis, 101-8430
Each speaker of Japanese would probably produce a different rendering.
It is interesting that the ku in Chiyoda-ku is not usually translated as “ward”. Note also the hyphen.
The order of the address is more or less reversed. Literally in Hepburn it would be: Kokuritsu Jōhō Kagaku Kenkyūjo 101-8430 Tōkyōto Chiyodaku Hitotsubashi 2-1-2
I have added spaces and capital letters. テcomes before the Japanese postcode.
研究所 may be romanized as kenkyūjo or kenkyūsho. NII prefers the former, but machine transliteration would produce two possibilities if it did not know this specific organization.
There are some other Romanizations in fairly common use in Japan e.g. Kunrei-siki and these cause confusion. One may see, for example, Hitotubasi instead of Hitotsubashi and frequently an address in Hepburn may have a couple of spellings borrowed from another system.
I am not aware of a Romanization that officially spells out long ō vowels as in e.g. jōhō as ou, but one sees this frequently e.g. jouhou. The officially Hepburn way of doing it, if one has no access to macrons is joohoo. One also sees jôhô (borrowed from Kunrei-siki).
