How much responsibility does Hirohito bear for the aggresion and actions of Japan in WWII

by modernafrican

I have just finished reading Jean Edward Smith's biography of FDR one if the things that intrigued me was the involvement of the emperor, in the events leading up to the beginning of the war.

on September 5th 1941 the emperor reprimanded the army chief of staff for his false estimate of the war with China (Konyone memoirs quoted in H. Feis the road to pearl harbor)
on September 6th 1941 the emperor chaired a privy council meeting that put a hard timeline on negotiations with the USA
The emperor directly intervened to make Tojo PM
on Dec 1 1941 the emperor was at the privy council meeting that pted for war

The emperor was a central figure in Japanese life and in a governmental system that borrowed a lot from Bismark's imperial German system the emperor had a lot of power (and i direct line to the army). Thus my questions are

is responsible Hirohito for the course that the Japanese empire took and the brutality (i.e. Nanking) that was perpetrated by Japanese forces?
Could he have stopped the march to war and could he have reigned in the armies brutality, if so why didn't he?, if not why couldn't he?
How does modern Japanese and foreign historiography deal with emperors role in the conflict?

You might be interested in some previous threads on the involvement of the Emperor of Japan in Japanese expansionism in the 1930s and 1940s:

Why wasn't Emperor Hirohito tried at the International Military Tribunal for the Far East after WWII? Why did the Allies let him stay "in power?" - 4 comments, over 1 year old.
This thread summarizes the general level of involvement that the Emperor had in Japanese military operations and activities throughout World War II.
To what extent was Emperor Hirohito aware of the operations of Unit 731? - 5 comments, over 4 months old.
A commenter in this thread goes into specific interactions that the Imperial family had with Unit 731 and related administration.
How did post-occupation Japan view Hirohito and were there large groups still loyal to him? - 41 comments, over 1 year old.
Commenters in this thread explore a variety of aspects of Emperor Hirohito, from the way his surrender speech sounded to the masses to extent of his involvement with Japanese politics and expansionism.