What is Hikkoshi-Soba?

Answer 1

From what i first read, Hikkoshi-Soba is soba you give to your neighbors when you first move in. Usually you give it to the houses on each side of your house and the three across the street (mukou sanken ryodonari) in apartments you need to give it to your floor neighbors and to the ones up one floor and down one floor. But then I read that you usually eat it when you just move in. From a resource i read and it turns out this isn't very traditional anymore. Of course you need to give a small gift to your neighbors but it isn't very customary to give soba anymore.

When and why did this tradition start?

During the Edo period (1603 to 1867), in Tokyo, it was custom to give beans to new neighbors. Soba was a rage during that time so people started to give favorites foods (soba in this case since it was really popular) to their new neighbors because one, soba was popular, and two, because it was cheaper than beans.

Another reason to give soba was because the shape of the soba noodle, which is really long, symbolizes hope for a long friendship, a lot like toshikoshi soba for New Years, and maybe it is a play on the word itself, soba (ni), since soba ni means close by. Like this pun: Osoba ni suenagaku otsukiai wo yoroshiku. Which means best regards for many years of friendship by your side.

Resources: http://blue_moon.typepad.com/blue_lotus/2005/11/hikoshi_soba.html