The new show has been made more accurate to the time period, they had historical experts come in. Plus the guy who plays Toranaga is an amateur historian of the time period and helped a lot.
That's all well and good but I'd have preferred they keep some of the story points from the book like the emphasis on Blackthorn learning Japanese, and the theming overall of the book being how Blackthorn perceives the Japanese vs what it is now where it's more of how the Japanese perceive Blackthorn. Still a good show.
My grandfather was a submariner in the Pacific during the war, they were even inside Tokyo bay during wartime. He had many stories, one of them was that the batteries always got the priority in regards to water. Especially on patrol and missions, they would often go days between wiping themselves down with hand towels from a basin of shared water, all to preserve the fresh water for the batteries.
He was on the Saury