The parameter is the year in the Gregorian calendar. The parameter can either be the article name for that era, or the era's name in kanji. (Transcribed English era names can usually be used, but will not work if they are ambiguous.) Either or must be specified. If both are specified, the module defaults to using to get the era data. This enables output of the last year of the previous era (for example, Shōwa 64 is the same year as Heisei 1).