Without any knowledge of what's available literature-wise in Japan, or if the author reads untranslated English literature, I can't make any guesses concerning 'influences' from earlier works in the field.
It's clear she's a decent grasp of stuff related to late Medieval/early Renaissance society and culture.
A decent grasp of the history of 'how we preserve knowledge for future reference'; better than mine, truth be told.
Published works that have been brought to mind while reading this series, but not as inspirations.
Lest Darkness Fall by L. Sprague de Camp.
The 1632verse created by Eric Flint.
Rather less so...
Various works by S.M Stirling.
Lord Kalvan of Otherwhen by H. Beam Piper
These all have differing takes on the concept of someone (or a group of someones) with modern knowledge being plunked into either the past or an alternate present, and how their dissemination of said knowledge impacts things. They all have a heavy focus on the impact upon military affairs, although the first mentioned rather less than the others iirc...
Other web fiction...
The Somewhere Else Entirely universe created by Penny Lane, over at Top Shelf Big Closet. (If you aren't familiar with this series, go read it now. Do not pass Go, do not collect $200, just go read it now.) Deals nicely with the quandaries of what knowledge to release when, and how to do so with minimal negative impact upon the existing social and economic structures, or at least I think they've done well at it.
Wait.
One inspiration I'm pretty sure of...Quidditch, anyone?