Well, the obligatory first suggestion would be the well-renowned "Shōgun", by James Clavell. Probably one of the most popular books to ever be written that's set before and during the 1600s in Japan. Older, but still holds up to this day, and gives some interesting perspectives to the Battle of Sekigahara.
Another popular pick of that sort of fiction would be "47 Ronin", by John Allyn. Or alternatively, there's "The Tokaido Road", by Lucia St. Clair Robson, which is essentially just another take of the very same Japanese legend. I personally like "The Tokaido Road" just a little more, but both stand very well on their own.
But, if you want something from that era that's a little more different, I would highly suggest "The Tales of Otori", a series of five books (includes the actual trilogy, a one-off sequel, and then a prequel) written by Lian Hearn. They're classified as 'Fantasy', and take place in "a fictional world inspired by Feudal Japan", but still carries the same thematic ties, realistic societal structure, and appropriate culture to associate it with Sengoku era Japan. Plus the story is just all around interesting, always a plus.
"Taiko", by Eiji Yoshikawa, is another really good option, especially if you're into the inner-workings and nuances of war of the times. Kind of old (published in the 1960's, I think?), definitely more on the historical side, but I found it an interesting read.
Some of the more eh titles that relate to this category are things like "Sisters Of The Sword" series by Helen Hart (not too terrible or anything, just a bit on the basic side), "Death At The Crossroads" by Dale Furutani (great mystery story, tbh), the long as fuck "Sano Ichiro" series by Laura Joh Rowland if you get desperate enough (I only made it through a couple of them before I got bored, but that could just be me.) Other than that, there are quite a few different stories inspired by the 47 Ronin legend out there, some more interesting than others.
Oh, and there was a somewhat recent (as in, published in 2017) YA novel called "Flame In The Mist", by Renee Ahdieh, that's set in Feudal Japan. Haven't read it myself, but it has a lot of good reviews regarding both the prose and the choice in setting, so that could be something of interest for you.