It was far from "very militaristic", and more so flat-out a Junta. Before the assumption of power by Tojo, the prime minister was "led from below" by a discontent and influential military group, and Prime Ministers were frequently killed or ousted by powerful shows of force and intimidation from the military elements. The military's control switched from de facto to actual when Hideki Tojo assumed the position of Prime Minister. Tojo's predecessors were either sympathetic to the military, from the military, or openly controlled by the military.

From the period mentioned, almost every Prime Minister was either a retired, or currently serving member of the IJA or IJN. This, of course, culminated in the Hideki Tojo holding the positions of both Prime Minister and Minister of War at one and the same time. This should be telling in and of itself as to what little pretense was left in hiding the militarized nature of the government of Japan.

As a general rule, the Showa Emperor was the end-all of power, and simple statements from him had demonstrated his political influence. The period leading up to 1937, and even after, was subject to multiple military coups and revolts by junior and middling officers. In almost every instance, the revolts were broken up by an issued statement from the Emperor. In one instance him simply telling the perpetrators to return to their Barracks at once. While its still a matter of great historical debate as to how much direct input Hirohito had - and how often, its safe to say he held sway and was present more often than not. Many orders from the ministry of war being superseded at times by decrees from him.

However in practice the Prime Minister, once Hideki Tojo assumed his dual positions, exerted the greatest influence. Up until that time it had been a fairly anemic power, ousted often or outright assassinated from elements from within the Imperial Army and Navy.

Source: Yenne, Bill; The Imperial Japanese Army: The Invincible Years 1941-42