If a person mistakenly recited Al Ha知ihya in a situation where he was required to recite Birkat Ha知azon, must he now recite Birkat Ha知azon? The Beracha of Al Ha知ihya is recited over grain products other than bread, whereas one who eats bread is required to recite the full Birkat Ha知azon. If a person ate bread and mistakenly recited Al Ha知ihya, must he then recite Birkat Ha知azon, or do we say that he fulfilled his obligation through his recitation of Al Ha知ihya?
Rabbi Moshe Halevi (Israel, 1961-2001), in his work Birkat Hashem (vol. 2, p. 270; listen to audio recording for precise citation), cites authorities who maintain that the Torah obligation of Birkat Ha知azon does not require reciting three separate Berachot. Although the Birkat Ha知azon we recite indeed consists of three separate Berachot (and a fourth Beracha which was introduced at a later point), this format was instituted by the Sages. As far as Torah law is concerned, however, one fulfills his obligation even by reciting a single Beracha, provided that this Beracha incorporates the themes of the three Berachot of Birkat Ha知azon. This is the view of Maran (author of the Shulhan Aruch), both in his Bet Yosef (Orah Haim 191) and in his Kesef Mishne (Hilchot Berachot 2:2).
According to this view, then, one who mistakenly recited Al Ha知ihya when he was to have recited Birkat Ha知azon has indeed fulfilled his obligation. Since the Beracha of Al Ha知ihya makes mention of the main themes of the three Berachot of Birkat Ha知azon, it suffices, on the level of Bedi誕bad (after the fact), to fulfill the obligation of Birkat Ha知azon. Therefore, in such a case, one is not required to recite Birkat Ha知azon, as he has fulfilled his obligation by reciting Al Ha知ihya.
Of course, it would be admirable in this case to wash one痴 hands and eat another portion of bread so that he can recite Birkat Ha知azon and thereby satisfy all opinions. According to the strict Halacha, however, this is not necessary, as he has fulfilled his obligation by reciting Al Ha知ihya.
Summary: If one mistakenly recited Al Ha知ihya instead of Birkat Ha知azon, he does not then recite Birkat Ha知azon. If he wishes to be stringent, he should wash his hands, eat another portion of bread, and then recite Birkat Ha知azon.
