Because I didn’t know if I would feel up to trying the challenge, I didn’t make any announcement post. But now that I have actually completed it, I wish to add a post with my results.
My 24-hour time frame was Saturday 12:45 to Sunday 12:45.
The “book” I picked was the visual novel 薄桜鬼 真改 風華伝. I’ve been reading it for a while now and picked it for this challenge to make more noticeable progress.
I can’t give an accurate word or character progress number as I’m reading the physical Switch version. That’s why I tried making a rough guess and got 22’550 characters out of my calculations which I added to the results below.
Explanation behind my logic for the character count
When I look at the bare minimum of one word reactions/comments/responses such as「…」, 「えっ？」,「NNさん」, 「そうですか。」and the like for one text box which span anything between 3 up to 10 characters, I’ll assume a minimum average of 5 characters for one text box to keep it simple.
Whereas the maximum box capacity for each line – 3 lines are the maximum per box – might be 25 characters each, I rarely saw that happening. Usually, it’s about 15 characters for each line if the box is filled with 3 lines, so that would mean an average of 45 characters.
Therefore, I’ll use this average minimum and average maximum and divide it by 2 for the average characters per box → 5+45/2 = 25 characters
I ended up using these presumed 25 characters for my estimation. If I multiply the 902 textboxes by 25, I get 22’550 characters.
Again, this is a very rough estimation since it could be off by several thousands of characters but it’s the only possibility I have without going down a rabbit hole and trying to find more chapter specific numbers online which I don’t fancy doing.
I don’t know if my logic makes sense (wouldn’t be the first time that my math isn’t math-ing) but I hope that this number is acceptable.
Final result 
Time spent reading: 6 hours and 37 minutes
Progress estimate: 5% of chapter 3 → 30-ish% of chapter 3
Textbox count: 902
Character count estimate: 22’550
Thank you very much for organising the Readathon, @taiyousea! 
Also, it’s really interesting and inspiring to see everyone’s thoughts, results and progress updates so far. I hope that everyone who isn’t done with the challenge yet keeps having a good time. 
It was supposed to be rainy today, but that seems to have shifted to tomorrow onwards. 
It’s the 3rd or 4th short story collection in the Galileo series I’ve read so far, and while I still prefer 東野圭吾’s long format writing, this was my favorite of the short story collections. The last case in particular I thought was really good! 
) and so I didn’t manage to read as much as I had hoped, but still. First I read that week‘s assignment of 点と線 (52 pages) and then I started this week‘s reading of 変な家 (7 pages) before running out of time. So I did not manage to address my book backlog but I was at least able to keep the current book clubs in check, which I think is a win as well 