Words associated with the new year used in the old calendar days were classified as season words for spring but, since the calendar reform in Meiji, the new year changed to the winter time whereby a separate section for 'new year' in addition to the four seasons was established.
そのため、旧暦時代の新年に関する言葉は春の季語に分類されていたが、明治改暦以降、新年が冬に移行したため、四季とは別に「新年」の部が設けられた。