According to dGe-chos, Thon-mi created the following seven letters: ཙ་ཚ་ཛ་ཝ་ཞ་ཟ་འ།. According to him, all of these seven letters were initially marked with a hook called “tsa-limb” (tsa lag) or “tsa-sign” (tsa rtags), which can be seen even in ཝ་ཞ་ཟ་འ་ in some archaic writings. As for ཝ, it is not a combination of ལ and བ but of འ and བ. Why does the superscript in ཝ look like ལ? Actually it is not ལ at all but འ with a hook (dGe.chos-1: 268.1–271.3).