Maybe. The Army, however, was not exactly a free agent. The decision-making timeline is relevant for our purposes here. In April 1941, the Matsuoka mission visited Germany and the USSR on a mission to try to expand the Nazi-Soviet commercial pact to include Japan. When Matsuoka visited Berlin, the Nazis basically ignored his proposal and instead encouraged Japan to attack Singapore (!). The Soviets signed a neutrality pact with no commercial agreement. However, the pact was of very limited utility because of the Army's propensity to just fight regardless. What the Matsuoka mission did help to do was create confusion. By June, there were several different groups arguing for different plans in the Army alone (to say nothing of the government). War Guidance wanted to invade southern Indochina. Operations failed to make up its mind but recommended flexibility. Military Affairs wanted some sort of vague attack on the British and/or Americans. Meanwhile, the Navy strongly disagreed with an attack on the USSR because it would conflict with the southern strategy, and Matsuoka (!!) demanded an invasion of the USSR. Finally, Anami Korechika wanted more troops in China to facilitate an attack on Changsha. After the outbreak of the war, the general staff submitted an estimate that suggested war in Siberia was only feasible if the USSR withdrew half of its infantry (15 divisions) and two-thirds of its air force from the Far East. If the Kwantung Army were built up to General Staff recommendations (eventually 22 divisions, with 16 in the first wave), the General Staff believed it would have a two-to-one advantage due to the smaller size of Soviet divisions. The operation would also require full use of all Manchurian railways and the reassignment of something like a third of Japan's rolling stock: a massive logistical effort even for the famously logistically averse IJA. And if this massive set of preparations were to swing into motion before the end of 1941, then the Japanese would have to decide almost immediately: before the end of August, or the attack would have to be postponed. The numbers are clear: the Red Army did not reduce its Far Eastern forces quickly enough to meet the IJA's timetable. Instead, mobilization continued, but at a slower pace, until the first echelon of 16 divisions was massed (early autumn). They were to remain in readiness for an invasion in the spring of 1942. Meanwhile, the General Staff's prized flexibility would ensure commitments against the Western powers and against the Chinese could also continue. Only after the American oil embargo, imposed largely because of the invasion of southern Indochina but also to forestall the Japanese mobilization of the Kwantung Army, did war against the West become virtually inevitable. The same embargo also vastly reduced the likelihood of a war with the USSR, because while the Army possessed the straight-leg infantry for a march to the Urals it lacked the fuel to run its mechanized, motorized, and air units for two years (to say nothing of the Navy's deficiency). From the Army's point of view, war against the USSR was the primary mission. (And, as several people upthread have pointed out, it was ironically monstrously inadequate to fulfill that mission.) But the side conflicts that prevented the Army from massing its full strength against the Soviets weren't just distractions. They were in large part byproducts of the Army's own methods for achieving the goal of defeating the USSR. And many of them, like the oil embargo, were not really the sorts of things that they could ignore. This is where Khalkhin Gol really mattered. Before 1938-39, the IJA was institutionally confident of victory over the Red Army. After Changkufeng and Nomonhan, that was no longer the case. The IJA's demand of two-to-one operational superiority in the Far East is astonishing when compared to the sorts of ratios it regularly massed against even, say, the Americans, to say nothing of the ratio of 1904-05. Had they not been defeated so soundly, perhaps the estimate would have changed to one that IGHQ could have supported. Whether that estimate would have been realistic is another matter. Despite literal decades of preparation, the IJA was woefully unprepared to fight in Siberia from a logistical and operational point of view and had little means of inflicting a decisive defeat on the Red Army. There was not much, if any, prospect of cooperation with Nazi Germany. I think that the general verdict is that Japanese involvement would not have helped Hitler that much and that the Japanese were primarily there to pick up the pieces of a defeated Soviet Union. He wasn't equivalent to Hitler and Mussolini. He was very visible, but was mostly brought in as prime minister to try to get everyone working in the same direction (which Konoe had failed to do and for which he was removed after the chaos of the Indochina debate). He failed in that goal, as well, although he was arguably better than any other Showa prime minister at getting the Army and Navy to kinda sorta not really cooperate. Tojo was responsible for monstrous orders and war crimes but never came close to appropriating the sort of national demigod language or imagery as the other two Axis leaders did. If anything, crossing the Gobi Desert, Altai Mountains, and Central Asia would have been even more of a logistical nightmare than a more northerly route. The Tang dynasty didn't have mechanized armies, and didn't try to sustain a million-man army in Central Asia. The Qing dynasty didn't have a million-man army either, but it still took the Qianlong Emperor and his predecessors literal decades to build up the logistical infrastructure to fight the Zunghar Wars. Fighting through the Tarim Basin wasn't a serious consideration for the IJA. Nor was it a serious consideration for the USSR when the time came for the Manchurian Strategic Offensive Operation in August 1945. Neither option was incredibly feasible, but the slightly-less-ridiculous one for Japan was the one that attempted to use existing rail infrastructure. Yes. Operationally, Japan did not have to attack the Philippines to invade the South Seas and the IJN's institutional failure to notice this was a massive strategic error. US Navy assets in Manila Bay were vanishingly small. Any one of the invasion convoys dispatched south could have made short work of them with its organic naval assets, to say nothing of the massive combat fleet waiting in the wings. The only other strike force available was the set of B-17s at Clark Field, which the Americans erroneously believed could interdict ships maneuvering at sea and create a vast "no-go" zone around Luzon that would prevent the Japanese from moving south. This was a comically exaggerated view of the effectiveness and accuracy of high-altitude level bombing and there's not even any evidence to indicate that the Japanese shared this view. Simply put, there was no reason to preemptively strike even the Philippines, let alone freaking Hawaii. Attacking Britain was probably inevitable, because of the importance of Singapore, but fighting the Americans could wait (if it ever happened). Some American starred officers commented after the war that this might have been Japan's best option, and it's hard to disagree. Please don't. The sticking point for me is the oil embargo, which was fundamentally about Japan's China policy and its preparation to invade the USSR. (And the China policy itself constituted a leg of the preparations to invade the USSR.) There was no consensus for a southern invasion until after the oil embargo, with good reason. The oil embargo made it necessary.