I'm going to be working in Tokyo later this year & would like to start a RTW (including London, some of Europe, NYC, San Fran, New Zealand & Australia) in Business or First from there or somewhere nearby.

I'm actually based in Sydney, AU but from what I've read it's going to be cheaper buying and commencing this fare from Asia.

Do any of you smart FT-ers have any suggestions on how I should tackle this?

An interesting option for you could be to look at the Global Explorer fares, available cheapish in business class from Fiji (about AU$6800+taxes) or even cheaper from Tonga (about AU$5800+taxes). There's a direct flight from Fiji to Tokyo on Air Pacific that you can take, and earns full SC's in the QFF program too. Given the places you've listed wanting to see, 34,000 miles should be enough, the only big issue might be the 2 stopover limit in the region of origin, depending on where in Aus and NZ you wanted to go.

Otherwise if you're looking for the OW Explorer, then Bangkok is probably the best place to be starting for a location near Japan, or Colombo is even better if you can find yourself a cheap flight in that direction.

OK Thankyou GibSpmuh for that great advice.

I don't really need to include any of AU or NZ in the trip, I just thought I might return home before completing the trip. So if we remove that from the equation it probably works out easier.

Work will get me to Tokyo and then I will probably be working in NZ a little later. I thought to bridge the gap between cities I might go traveling.

Therefore I could do my RTW and then take the return home from Tokyo (that work will pay for).

Great way to start a RTW isn't it? Not having to buy flights to get you to the starting city.

And when it comes to it: where do I buy my Global Explorer ticket from?

You should be able to get a Global Explorer ticket from anywhere that can sell you a OneWorld Explorer ticket. You might want to liaise directly with one of the airlines on this, or if you know a travel agent in whichever country you want to start things off in, you could go through them. No doubt suggestions can be found on travel agents depending on which country is of interest.