Q. I see that the second day of Pesach is the same day of the week as the first day of Shavu’ot. Is this just a co-incidence?
A. Not at all. It is part of a well-known mnemonic device known as at-bash (אתבש) whereby the first and last seven letters of the Hebrew alphabet are matched up (thus alef = tav and bet = shin).
Since every Hebrew letter has a numerical value, you take the letters alef to zayin, representing the first seven days of Pesach, and you can link them with the letters tav to ayin, the last seven letters taken in reverse order, to indicate which day of the week seven other festivals will fall.
Thus you get the following pattern:
Alef (1st day of Pesach) = Tav, Tishah B’Av
Bet (2nd day) = Shin, Shavu’ot
Gimel (3rd day) = Resh, Rosh HaShanah
Dalet (4th day) = Kof, K‘riat HaTorah (“Torah reading”, i.e. Simchat Torah)
Hay (5th day) = Tzaddi, Tzom (“Fast”, i.e. Yom Kippur)
Vav (6th day) = Pay (Purim)
Zayin (7th day) = Ayin, (Yom) Atzma’ut.
Whilst the general concept of at-bash as applied to the first six days of Pesach was well known for centuries, it was not until the creation of the State of Israel and the institution of Yom Atzma’ut that it was recognised that the 7th day of Pesach, represented by zayin, now had a calendrical partner. This was pointed out in a publication called “Tikkun Yom HaAtzma’ut”, issued by the Israeli Chief Rabbinate early in the history of the Jewish State.