This question already has an answer here:

I've been reading more Japanese literature, and in doing so I've come across hiragana with something that looks like 、to the right of some characters where ふりがな would be (keeping in mind that Japanese is written from top to bottom in books. It's not a comma, and it seems to usually appears on hiragana in succession.

I was thinking it was for emphasis, something like italics, but don't know what it means for certain.

I've attached a picture to clear up any confusion as to what it looks like. They're on the very right of the image by 「いわし」.

enter image description here

marked as duplicate by senshin, Dono, blutorange, ssb, Kaji Feb 18 '15 at 9:26

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.