Toshikoshi-soba (Buckwheat Noodles Eaten on New Year's Eve) is a term for buckwheat noodles which are eaten on New Year's Eve (December 31st) for good luck.
Currently, this custom is observed throughout Japan. It is said that people must eat all of the soba (buckwheat noodles) they are offered before the new year dawns, or else they will be unlucky with money in the coming year.
Originally, around the middle of the Edo period, people habitually ate 'misoka-soba' (literally, "buckwheat noodles for the thirtieth day of the month") at the end of each month, and the New Year's Eve soba is believed to be the last surviving remnant of this custom.
The most commonly held explanation for the origin of Toshikoshi-soba is the wish for a 'slim but long and healthy life,' like buckwheat noodles. Another theory is that, since soba noodles are easily cut, they express the hope that all burdens imposed during the last year will be "cut off" and not carried over into the next year; however, this explanation is believed to be newer than the custom.
Toshikoshi-soba noodles in different regions
In the Aizu district of Fukushima Prefecture, soba noodles are customarily eaten on New Year's Day instead of New Year's Eve; in addition, "mochi" (sticky rice cake) is eaten on the second day and "tororo" (grated yam) is eaten on the third day of the New Year.
In Niigata Prefecture, soba noodles are customarily eaten on the fourteenth day of January (the eve of the lunar New Year), when they are called 'Juu-yokka soba' (literally, "soba noodles for the fourteenth day), as well as on the first day of January (New Year's Day) instead of New Year's Eve. In the Kita Ward of Niigata City (formerly Toyosaka City,) it is common to eat soba noodles at midnight on New Year's Eve.
In Fukui Prefecture, many people eat 'oroshi-soba' (soba noodles with grated daikon radish, also known as "Echizen soba" or "soba noodles of Echizen province") which is made by pouring a strong broth diluted with grated daikon radish over soba noodles and adding green onions and katsuobushi (small shavings of dried bonito).
There was formerly no custom of eating soba noodles on New Year's Eve in Okinawa Prefecture; however, many people have recently begun to eat soba noodles in this way, although many of them eat Okinawan soba noodles instead of "Nihon-soba"noodles (literally, Japanese buckwheat noodles).
Additionally, in some regions, people eat salmon fillets, sardines and similar things on New Year's Eve.
There are also regions in Japan where the custom of eating soba noodles on New Year's Eve is less popular. For example, in Kagawa Prefecture, people customarily eat Sanuki Udon (udon noodles from Kagawa Prefecture, formerly Sanuki Province) instead of soba noodles. Sanuki Udon noodles have become so well-known that even a nationwide news program showed scenes from a Sanuki Udon shop in Kagawa Prefecture together with scenes from a soba noodle shop in Tokyo.