I know something about both Chinese and philology, but not much, so please explain like I'm 20. :)
I'm looking at a text on Wikisource dealing with "the Shû King". It refers to "Mo-3ze" (Mo-zi) and "Hsün-3ze" (Xun-zi), and someone called "3o Khiû-ming" — where I'm using the ASCII letter "3" to represent the crazy, on-beyond-zebra letter that the typesetter actually used.
In lowercase it looks kind of like a cursive z or an ezh, but in uppercase I have no idea what's going on: it's like a 3 with cleavage, plus a circumflex accent hanging off its lower horn.
Notice that this Romanization system also seems to use significant italics; e.g. "King" is a different word from "King". (And in both cases "K" denotes what we'd call "J" these days — as in "Peking".)
What is the name and/or Unicode codepoint of this character? What sound is it supposed to represent? And whose Romanization system are we looking at here?