@Caesar:
as for the Japanese, they are not allowed two sea zones within US mainland.
Which exact sea zones are Japan actually allowed/restricted?
Just count two SZ from Alaska, Western US, and Mexico.
Can only USA/USSR sea units share territory with all others when not yet at war? Or only with Axis or Allies? I assume land units may not share space.
Sea units may share a sea zone with anyone. Land units may not enter another power’s territory, and no other power’s land units may enter their territory.