Tu B’Av means the 15th day of the month of Av in the Hebrew lunar calendar. The tet and vav (which make up the word ‘tu’) represent 9 plus 6, i.e.: 15. Tu B’Av is a lesser-known, minor holiday of the Jewish calendar, signifying the end of the solemn period of the Three Weeks.
A portion of the Talmud (Oral Law) states: “There are no days as festive to Israel as those of Yom Kippur and the fifteenth of Av. The daughters of Israel used to dress in white and go out to the fields to dance and young men would follow after them.” (Ta’anit 4:8)
This statement in the Talmud does not make clear what the festival of Tu B’Av celebrates. Some interpret it to infer that the afternoons of Yom Kippur and Tu B’Av are times set aside for forgiveness. The Jews had been wandering in the desert for forty years when God granted them entry into the Promised Land (Canaan) on this date, allowing the 15,000 remaining Jews to survive. It is believed that this was a sign that God had granted the Jews forgiveness.
There is also a link between this date and the Bar Kochba revolt in 135 C.E. Bar Kochba lead a Jewish army against the Roman domination of Palestine. Kochba fell at Betar on the 9th of Av, and it became apparent that the Jews had lost. Casualties were more than half a million. The Jews were further punished by being forbidden to bury their dead. This ban was lifted three years later on the 15th of Av, so again the date represents an idea of forgiveness.
In ancient times Tu B’Av was also the final date for Levite and other high-status Jewish families to bring wood offerings to the Temple. This is most probably the origin of the bonfire customs associated with the festival.
On Tu B’Av the daily prayer service is slightly altered, with an omission of the Tahanun (penitential prayers) which are usually recited during the Shacharit (morning) service. No eulogies are given at funerals on this date; these two traditions further indicate the end of the mourning period.
In Israel Tu B’Av is treated as a Jewish version of Valentine’s Day. People have picnics and go on hikes to re-acquaint themselves with nature and happiness, after the Three Weeks of sadness. It is a very popular date for singles events and also for weddings.
Tu B’Av is a time that should not simply be overlooked for its lack of mention in the Torah. It sets aside a specific time for communication and rejuvenation, which is necessary for the coming High Holidays.
Jewish Virtual Library: Tu b’Av
Chabad: The 15th of Av: Love and Rebirth