I recommend reading Herbert Bix’s ‘Hirohito and the rise of modern Japan’. I haven’t found a book yet that better encapsulates the many sides of this powerful issue. And, having lived in Japan since 2006, I can tell you that Bix hits the nail on the head with his analysis of Hirohito’s guilt (or innocence) and it’s impact on modern Japanese thought. At a time when Japan seems unable to lead in Asia, this book is especially relevant.