This version of Birkat Hamazon is based on the views of the Rambam and the other Rishonim. If one is unable to say the full version that is customary, one may say this version, even initially as a first choice. Rabbi Yitzchak Abadi Birkat Hamazon Hakatzar. Birkat HaMazon Hakatzar Mein Shalosh. Tefilat HaDrech.