What Japanese New Year's dish of buckwheat noodles symbolizes longevity?

Toshikoshi soba is the Japanese New Year's dish of buckwheat noodles associated with longevity.

The name toshikoshi soba means “year-crossing soba.” People commonly eat the noodles on New Year's Eve, either shortly before midnight or during the evening. Their long, thin shape is linked symbolically with a long life, while the ease with which buckwheat noodles can be cut is sometimes connected with leaving behind the hardships of the old year.

The custom became widespread during the Edo period, although explanations of its exact origin vary. Ingredients and toppings differ by region and household. Tempura, green onions, fish cake, and other additions may appear, but the defining feature is the soba itself.

Toshikoshi soba should not be confused with osechi ryōri, the assortment of auspicious foods served during the first days of the new year. Nor is it the same as ozōni, a New Year's soup whose ingredients also vary by region.