Now, I've been reading 竹取物語 and have come across (another) set of symbols that I've yet to understand. Given the following sentence.
What does the sudden 「／＼」 mean?
This is supposed to be an iteration mark.
This type of iteration mark is usually only used in vertical writing (the traditional layout for Japanese writing). It looks like a big く but is twice as tall.
It also exists in Unicode, so I can try to produce it here, although it may not render nicely:
(Wikipedia does a better job and has more examples.)
／＼ are often (ab)used to represent the vertical iteration mark in horizontal writing.
やう／＼ = やうやう = ようよう = 漸う