Our mishnah first defines exactly when this ceremony is to take place. Basing itself on the words of the Torah we are offered a typical rabbinic conceit: the Torah [31:10] says that the ceremony of Hakhel is to take place At the end of every seven years, in the time of the Shemittah year, in the feast of Sukkot." This indicates that the ceremony is to take place once every seven years around the time of the last year of the seven-year cycle, the sabbatical year, Shemittah. (For more information on Shemittah click here and then navigate to mishnah 1, paragraph 20.) It also indicates that it is to take place during the festival of Sukkot. This is further defined as follows: "At the end" is understood to mean 'after the end' of the Shemittah. The Shemittah year ends with the onset of Rosh ha-Shanah of the eighth year (the first year of the new cycle); this year is known in rabbinic parlance as "motza'ei shevi'it". The festival of Sukkot occurs on the fifteenth day of the new cycle and lasts for seven days. However, the Torah states that the ceremony is to be held 'in the time of the Shemittah year, in the feast of Sukkot'. "In the time" renders the Hebrew "be-mo'ed"; "mo'ed" in rabbinic parlance indicates the non-sacred days of the festival ["ĥol ha-mo'ed"], and, in Eretz-Israel the first of these days is the second day of the festival. Thus the first opportunity for the Hakhel ceremony is on 16th Tishri immediately following the end of the Shemittah year - and the Gemara [Rosh ha-Shanah 32b] tells us that "the diligent perform a mitzvah at the earliest opportunity".
4:
The same hierarchical order is observed when providing the king with a sefer Torah from which to read as is observed when providing the High Priest with a Sefer Torah from which to read on Yom Kippur (see previous mishnah for details and explanation).
5:
The passages that the king is to declaim to the assembled people are detailed as follows: Deuteronomy 1:1 to 6:9, 11:13-21, 14:22 to 15:12, 17:14-20 and 26:12-19.
To be continued.