Buckwheat noodles are a speciality of Japan.
Soba has been eaten in Japan since the Edo period.
I already mentioned the special New Year tradition of eating them.
They are made using buckwheat flour (or at least a mix of buckwheat and regular flour) which gives them the brown appearance.
They are often eaten cold with “men-tsuyu” – a soy based watery sauce
(面・men is Japanese for noodle, and つゆ・tsuyu is a kind of dipping sauce).
As you may know, any thin noodle can be called “soba”.
For example, yaki-soba is a kind of fried noodle with sauce that is a popular festival food.
Okinawa also has a unique kind of soba – it’s a mix between ramen and udon and often served with meat and is more oily.