Halachicly sound ways to bookmark on Shabbat

Question

I would like to know if there are any ways people are using to bookmark/highlight what they are learning on Shabbat, so they can come back to it after Shabbat to make notes etc.

Putting in a bookmark isn't always useful, if the page has enough content on it, so are there any improved ways of highlighting on Shabbat that are halachicly sound?

For example, Post it notes, and folding the page might be suggestions, but they are controversial.

Happy to hear all suggestions, but ideally practical ones. Remember, one might continue learning the sefer after the bookmark, so something that could easily be disturbed, or would make it impossible to continue using the sefer would be quite impractical.

Answer 1

As I wrote here, folding the corner of a page is permitted and a good way if you don't mind "damaging the page" a bit. Still your question goes beyond, and you note the issue of marking a specific place on the page.

The best solution I found for this are book darts - these are small metal arrows which pince the page at a specific location and can be removed without any trace. R Gil Student researched them (here) and found them to be mutar to use on Shabbat. He goes through the sources and concludes

It seems that most authorities would allow the use of book darts and bookmarks on Shabbos because it does not constitute preparation for after Shabbos. Additionally, when I use bookmarks on Shabbos, I often refer back to the book on Shabbos. In other words, placing the bookmark or book dart is for Shabbos itself and not (just) preparation for after Shabbos. This would allow even more room for leniency.

I have very positive experiences with this specific product which exists in a version called "I read this over Shabbos" (for the movement of those who post on twitter after Shabbat what they read that day).