January 1st (in the old calendar) {which is around the start of spring in the calendar and which is around February in the Gregorian calendar (the new calendar)} according to the old calendar (in Japan, the Tempo calendar) is called kyu-shogatsu (old new year).
旧暦（日本では天保暦）の1月1日(旧暦)｛立春前後、グレゴリオ暦（新暦）での2月頃｝は旧正月と呼ばれる。