Two Days As One Day

How many days is Rosh Hashana? It seems the simplest of questions, since all
around the world, no matter where you may be, Rosh Hashana is celebrated
for two days (as opposed to the first and last days of Passover,
Shavuot, the first days of Sukkot and Shemini Atzeret – all of which are
observed as one day in Israel and two days elsewhere).

The Torah commandment to observe Yom Teruah
(the Day of the Sounding [of the shofar]) states that the holiday is to
be observed on the first day of the seventh month.* It is the only
holiday that occurs on the first day of a month. The Jewish calendar is
lunar based and, until approximately 350 C.E., the declaration of the
new month was dependent on two witnesses reporting the appearance of the
new moon to the Sanhedrin. If the new month was declared late in the day, word still needed to reach those who did not live close to Jerusalem.

Wanting to prevent any possible desecration of the holiness of the day, the rabbi declared that the New Year be celebrated as a Yoma Arichta (Aramaic for one long day), meaning that the one day was spread over
two days. In other words, while Rosh Hashana is observed on the first
and second of Tishrei, the two days are thought of as a single day.

One of the more interesting effects of this transformation of two days into one is
the question of whether or not a person recites the Sheh’heh’cheh’yanu blessing
during candle-lighting (for women) or kiddush (for men) on the second
night on Rosh Hashana. On all the other holidays, the second day is
treated the same as the first. Since sheh’heh’cheh’yanu is also
recited over a new possession or a food that one has not tasted in over a
year, it has therefore become the custom to include a new fruit at the
beginning of the second night meal of Rosh Hashana and have the new
items in mind when reciting the sheh’heh’cheh’yanu blessing.