Hilchot Berachot 6:3-4 (How much of your hand do you need to wash for Netilat Yadayim?)
7:36 am
Is Mayim Acharonim – washing hands before Birkat HaMazon – mandatory? Are we more or less strict regarding Mayim Acharonim than we are for washing before eating? When ritually washing hands, how much of one’s hand must a person wash?