I know that this subreddit frowns on the use of websites as sources, but a good starting point for Japanese ships is combinedfleet.com. Before anyone crawls down my throat, the creators of that site are Jonathan Parshall and Anthony Tully, the authors of Shattered Sword which is probably the best book available on the Battle of Midway. That gives it some pretty legit credibility.

So to be clear are you looking more for a general overview of the fleets, their organization, makeup, and how they fought?

Or simply a technical history and overview of the ships themselves?

For the IJN CombinedFleet.com is indeed a wonderful resource I would recommend in a heartbeat. There are plenty of other good books too if you are looking, the Dulin and Garzke books on the battleships of the different sides is very good. Norman Friedman also is notable as a renowned author technical examinations of vessels from 1900 up through the Cold War and beyond, with particular emphasis on the world wars and interwar. He does mostly examine US and UK naval trends and issues but he may still be worth a look as he has nearly 2 dozen works over the years.

Otherwise if you could get a copy on an old edition of Janes it might be a neat anachronism and cool to see, but remember that it is limited by the fact that it was fundamentally not a Japanese source for instance, and the IJN could be extremely secretive when it came to ship specifications.