There is an obligation to recite the complete Hallel ("Hallel Gamur") on each of the eight days of Hanukah. This obligation applies regardless of whether one prays with a Minyan or privately. One recites the introductory Beracha before Hallel – "Ligmor Et Ha’hallel" – as well as the concluding section of "Yehalelucha" which ends with the Beracha, "Baruch Ata Hashem Melech Mehulal Ba’tishbahot Amen." The reason why one answers "Amen" to his own Beracha is because when a Beracha is recited at the conclusion of a series of Berachot, one recites "Amen," as we do each night at Arbit, when we recite before the Amida, "Baruch Ata Hashem Shomer Amo Yisrael La’ad Amen."
One may recite Hallel anytime from sunrise to sunset, as the verse in Hallel states, "From the sun’s rising until its setting, Hashem’s Name is praised" (Tehillim 113:3). Nevertheless, if one mistakenly recited Hallel before sunrise, but after Amud Ha’shahar (the point when light first appears on the eastern sky), he has fulfilled his obligation.
If a person forgot to recite the Beracha before Hallel, and he remembered before he completed the Hallel service, he may recite the Beracha at that point and then continue. As long as he still has some part of Hallel remaining to recite, he may recite the Beracha.
It is forbidden to make any sort of verbal interruption during the recitation of Hallel. However, if a person hears a Beracha as he recites Hallel, he should answer "Amen" to the Beracha. Likewise, one should interrupt Hallel to answer to Kaddish, Kedusha and Barechu. This applies only to the first five "Amen" responses of Kaddish; one should not interrupt Hallel to answer "Amen" to "Titkabal" and the later passages of Kaddish. If a person hears a Beracha, Kaddish, Kedusha or Barechu after he completed Hallel, but before he recited "Yehalelucha," he should answer "Amen," and does not have to rush to complete "Yehalelucha."
Women are exempt from the obligation of reciting Hallel on Hanukah, even though they are included in the obligation of candle lighting. A woman who wishes to recite Hallel on Hanukah certainly may, though she should not recite the Berachot before and after the Hallel recitation.
