The Hawaii thing still doesn't make sense to me. OP is going to take aeons (13-15hrs) first to go to Hawaii, then another 9hr flight to TYO? Going through Hawaii is such a roundabout way (and an expensive one) to get to Jpn. And I still don't see how that helps much with clock adjustment. MSP is only a couple hrs from upstate NY, and MSP is only 2.5-3hrs longer flight to TYO than HNL, actually. By the time he gets to Hawaii, he could just about be in Jpn.

Btw, my worst is having long (7+hrs) flights back-to-back. YYZ/ORD-HKG nonstops, no problem. But when we go USA to S.Africa, it's really rough. There's something perverse about having to step onboard an 11-hr flight at LHR when you haven't had the time to recuperate from an 8-hr flight you just came off of. Of course it'd help if you're in premium cabin, but that's not how most of us travel.

Has anybody visited europe on the way to Japan? How was your experience?

Ya, Hawaii isn't the best option, unless it's a destination of it's own on the way. In some ways I think I should just bite the bullet and make the long haul. But I wanted to explore the option of splitting it up before I go again.

As far as I can think of, about the only European gateways with flights <10hr to TYO would be something like Helsinki or Moscow. But then how are you going to get there? Otherwise just about everywhere else (eg, LHR, AMS) will entail a flight longer than what you'd like.

I would just bite the bullet if I were you. Even from YYZ, we're only talking 3hrs longer than from SEA, YVR or HNL. And you could just drive there from where you live. Once upon a time I used to live not too far from where you are. I've driven to YYZ to take the nonstop to Jpn.

Yes. on an award flight.

Toronto-Montreal-Zurich-HKG-Osaka then back transpacific.

I do not recommend a N America-Europe-Japan routing if your goal is to maximise comfort or avoid jetlag.

PS for the OP-start in Toronto, fly direct to Haneda on AC. If business class too much $$ keep an eye on Premium Economy fares. They go down to the $1700 Canadian range occasionally. or the lowest business class fares that you can get sometimes for $C3200 ~$US2400.

Thanks everybody for your comments. It was helpful.