The author actually does a pretty good job of explaining the Japanese political system as it goes. I think you do have to go in understanding at least a bit about the factional nature of Japanese politics, though, but I think it's at least moderately accessible without a very deep knowledge of it...
Just cautioning though that sometimes my TL will be a bit wonky because I use an MTL and then correct it afterward if I can, so sometimes I'll make a mistake and miss something (such as I originally wasn't sure what party names the author was going with because the MTL kept changing them, so early on, I just used the real life equivalents, however, when I actually figured out what they were, I made the change going forward). So, if you're okay with that, I think it's been worth a read.