[Sangetsu]

Ask your employer if they can get you a hanko before you arrive. My employer was nice enough to do this for me. If they can't get you one, I'm pretty sure there is a shop in Tokyo Station which can make you one (if they don't already have one in stock with your name).

It's simpler to bring cash with you. You'll have to pay a fee for converting your dollars to yen, but you'd have to pay a fee even if you wire the money, and there's a charge for wire transfers. You can bring up to $10k with you without having to fill out a tax form. Keep your cash in your carry-on bag. Checks are pretty much unknown in Japan, you may not have immediate access to your funds if you try to deposit a cashiers check.

As for banks, I recommend Shinsei Bank. There is a large branch on Yaesu-dori within walking distance of Tokyo Station. Just go out the Yaesu Central Exit from the station, it faces Yaesu-dori. Shinsei bank is at the third traffic light on the right side of the road. They have English speaking tellers there if your Japanese skills are lacking.

My gf likes Shinsei bank because they don't charge the fees which most other Japanese banks charge. I have an account with Citi, but I plan to close it and move over to Shinsei as well.