Problem is, you use those and the US will launch nukes at you. So, unless you have a Rekalian quantum inhibitor (should destabilize the fissile material in a standard nuke), you're SOL. There is LITERALLY no possible way to quickly take out Japan in an blitzkrieggy invasion. None. Zero. Don't sit here demanding that I invent something. Not even Guderian x Rommel ^ Von Manstein could invent such a scenio without the Zaldox'xian disrupter and Rekalian inhibitor.
Fighting the US means fighting these nations (all have mutual defense pacts with the US):
- New Zealand
- The U.K.
- The Netherlands
And for good measure, more than likely (due to their overwhelming dependence on the US):
- Saudi Arabia
Have fun taking them all out while you're at it.