This is a serious issue with the current diplomatic policies.
Japan does not fight with the Soviet Union. Nor does it garrision the borders near the SU. Vice versa with the SU.
They made a treaty, in which both sides agreed not to fight. This was the HUGE reason that the SU was able to beat off Germany. The entirety of the Moscow reinforcements in the winter of 1941 were of hardend Siberian troops from the Russo-Manchurian lines. (They left perhaps two divisions guarding the actually border of Korea/SU)
(Note, from now on, I refer to the SU as Russia)
Now, perhaps some sort of treaty could be made in the 1936 scenario, to give the player a choice of fighting. (As either Japan or Russia)
But the Computer should NEVER pick the fighting option (unless on V. Aggress)
Japan should not be able to go to war with Russia, and vice versia. Perhaps they could be given an event in which states "Reneg on the current pack? Or keep it" for both sides. Starting with Japan.
Event - Non-aggression pact with the SU
Japan
a) Stick with the non-aggression pact
effects= -5% dissent, unable to go to war with Russia at the start of conflict or when Japan joins alliance, prompts event Non-Aggression pact with the Japanese.
b) Reneg on the pack
effects= +10% dissent, -5 DI, goes to war when it joins alliance with Germany and Axis is at war with SU, or when Axis declares war on Russia (and Japan is already a member of axis), prompts event Reneging of the Non-agression pact with the Japanese.
c) Demand renegotiations and concessions or cancel pact.
effects= +5 dissent, demand Vladivostok, Ocha, Vanino, Ulunga, Dalnegorsk, Dalneretjensk, Chabarovsk, Spassk Dalnji, Nachodka,
prompts event renegotiations with the Japanese.
Russia
Event - Non-aggression pact with the Japanese
a) Stick with the non-aggression pact
effects= -5% dissent, unable to go to war with Japan at the start of conflict or when Japan joins alliance.
b) Reneg on the pack
effects= +10% dissent, -5 DI, goes to war when Japan joins alliance with Germany and Axis is at war with SU, or when Axis declares war on Russia (and Japan is already a member of axis), prompts event Reneging of the Non-aggression pact with the Russians.
Event- Reneging of the Non-aggression pact with the Japanese.
Effects= Notification of the fact that Japan has reneged on the Non-aggression pact, + 5 dissent.
Event- Renegotiations with the Japanese.
a) Deny demands and cancel pact
effects= - 5% dissent, prompts event Reneging of the Non-aggression pact with the Japanese
b) Accept demands
effects= +5 dissent, ceed demanded provinces. Prompt event Russia submits to our demands.
c) Declare war immediately in outrage.
effects= -10% dissent, prompts event WAR over demands.
Japan
Event- Reneging of the pact with the Russians
effect= +5% dissent, goes to war when Japan joins alliance with Germany and Axis is at war with SU, or when Axis declares war on Russia (and Japan is already a member of axis), prompts event Reneging of the Non-aggression pact with the Russians.
Event- Russia submits to our demands
effects= -10 dissent, gain ceeded provinces
Event- WAR over demands
a) Unfortunately, we will not back down. War it is.
effects= +5% dissent, immediate war between Japan and Com-Intern.
b) AVOID WAR AT ALL COSTS.
effects= +5 dissent, prompts event Japan backs down.
Russia-
Event- Japan backs down
a) Declare war anyways.
effects= +10 dissent, immediate war between Japan and Com-Intern.
b) Avoid war and accept Japanese stance.
effects= -5% dissent, Non-aggression pact is kept.
c) Avoid war, but reneg on the Non-aggression pact.
effects= prompt event Reneging of the Non-aggression pact with the Russians.
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Of course, if the computer was playing as both Russia and Japan, then the events would be A in both of the first events for Russia/Japan, i.e the non-aggression pact. If the player was controlling either japan or Russia, things could get interesting, especially depending upon aggression values.
Also, note that I haven't looked up the exact date of the pact. Yet these events can still be considered without it.