What is "Between Day"?

It is listed on the this website as an "upcoming event" on September 22, but when you click the link, there is no information.

I am just curious what this holiday is about? How do they celebrate it?

Japanese law states that if a single day falls between two national holidays, that sandwiched day will also become a national holiday. That's all!

Uji is right, it's just an extra holiday that is between two other public holidays this year- you'll see that there isn't one this time next year. No special significance at all other than enabling people to have 5 days off in a row.

also called a bridge holiday by some.

Sure enough it says "Between Day" on the Event Calender of japan-guide.com and you can even click it letting you end up in nowhere.
http://www.japan-guide.com/event/

I don't know how that English translation was made, but must say it's an appropriate interpretation. In Japanese we simply call that day "kokumin no shukujutsu" which simply means "national holiday." The other posters have already explained what that day is.

But the series of holidays between Sept 19 or 20 to Sept 23 is so-called "Silver Week" as it surrounds "Respect for the Aged Day" the day in which we respect those with "silver hair" so-to-speak. So in town, we notice some events related to the elderlies.

Oh, is that why? I had thought it was Silver Week due to its similarity to Golden Week- maybe both reasons are valid.

Yeah, I know what you mean, Sira :)
Here's some interesting info on the history of the phrase. I know it's just Wiki but still it's interesting.
http://ja.wikipedia.org/wiki/%E3%82%B7%E3%83%AB%E3%83%90%E3%83%BC%E3%8...

: I am just curious what this holiday is about? How do they celebrate it?

Here are two sorts of Japanese public holidays
: kokumin no shukujitsu [National Holidays];
: other public holidays.
A so-called "Between Day" such as 22 Sep. 2009 belongs to the latter.

Act regarding National Holidays [Holidays Act] states "what the holiday is about" only as to National Holidays.

As to other public holidays, Holidays Act just provides for which day shall be a holiday:
(a) If a National Holiday falls on a Sunday --- the later and closest day which is not a National Holiday shall be a holiday.
(b) If a single day is sandwiched between two National Holidays and is not a National Holiday --- the day shall be a holiday.

Rule (a) is to set a substitute holiday.
Rule (b) is to set an extra holiday. The day 22 Sep. 2009 was the first case where Rule (b) applied.

Until 2006, only the 4th of May could be an extra holiday.
Due to a revision of Holidays Act, since 2007, the 4th of May is a National Holiday, and an extra holiday can be set only in September for the present.

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