NEC PC-98
The PC98 was a series of computers produced by the NEC Corporation sold on the Japanese market and are to this day known as a series with a plethora of games made for them.
Emulators
Currently there are multiple emulators to choice from when it comes to the PC98, however they vary in quality. Dosbox-X is reported to have less accurate emulation, whereas Neko Project 21/W is the go-to for PC98 emulation. There is also Neko Project II which is closed-source, unlike Neko Project 21/W. Other emulators are not really useful and more of a historical note herein rather than actually software you would like to play your games on. This website offers a good overview of the various PC98 emulators available.
External Resources
https://gang-fight.com/projects/98faq/
https://en.wikipedia.org/wiki/List_of_PC-98_games
https://archive.org/details/PC9801Bible (Supposedly this book is good. I don't speak Japanese, so I got no clue whether it's actually good.)
https://tss.asenheim.org/ (A site for visual novels)