Port City Nov 13, 2014:

For clarity, what I mean by "area name" is what Japan Post calls 町域. Any address is shown in the following hierarchy: 都道府県>市町村>町域. In some areas, 町域 is further divided into 字(aza) (not shown in the Japan Post website), but that's not applicable here. My point is, after the merger, 湯布院町川上 has become the smallest unit in the area name (地名) system, and should not be divided into 2 separate layers as it was before. If it were an old address, it would be "3639-1 Kawakami, Yufuin-cho, Oita Prefecture" but that's no longer the case.

Port City Nov 12, 2014:

Japan Post shows the area name after the merger. It says ユフインチョウカワカミ, not カワカミ under ユフインチョウ. 「ユフインチョウカワカミ」as a whole is a name of the area. We all get influenced by what we know it used to be, but technically, 湯布院町川上 is now an area name just as 丸の内 is a name of an area in 千代田区.

The 2nd paragraph from the below link says 「2005年10月1日に郡内の挾間町、庄内町と合併し、由布市（ゆふし）となり自治体としては消滅した。現在「湯布院町」という地名は、旧町域にある大字の頭に付く形で残っている。」What the second sentence tells us is that what used to be 川上 is now called 湯布院町川上 as an "area name" (not as an area under Yufuin-cho).
http://ja.wikipedia.org/wiki/湯布院町

If it were an address of a hotel in Yufuin on its website, I wouldn't be so insistent on this matter.

PS. The document in question uses the address after the merger as it says 由布市, which was formed as a result of the merger.

Nicholas Sturtevant Nov 12, 2014:

In my experience J Post has been a safe standard Japan Post still lists an entry for the address exactly as it appears in Japanese, even if it has changed as you mention. Even if the political map has changed, the document in question is a certificate and as such should be translated as is, despite changing political circumstances. For example, on a much more exaggerated scale, a certificate signed in "Edo" would not be translated to read "Tokyo" despite that being the current designation. Again, according to Japan Post "Kawakami" appears as a 番地 like any other.

Port City Nov 12, 2014:

Until 湯布院町 was merged with other towns to form 由布市, 川上 was an area UNDER 湯布院町. But after the merger, 湯布院町川上 has become one area under 由布市, thus 湯布院町川上 is now on the same hierarchy level in the public administration/address system as what 川上 used to be. Expressing the area as "Kawakami, Yufuin-cho" is a legacy from the time when 湯布院町 had its own local government, but technically it's not necessary to put Kawakami under Yuruin-cho.