Fares to NRT have gone through the roof, as they say.
Last summer I bought a bunch on AC YYZ-YVR-NRT for $2,850 CAD. For months now, AC has nothing less that $5,000 CAD. Occasionally others have something in the $4,000+ CAD range.
Here's something to consider:
AC is launching a new non-stop in June YUL-NRT and I see fares at $3,665 CAD. That's decent when converted to USD and I'm sure easy enough to position to. The alternatives are not worth it: YYZ-YVR-NRT is still over $5,000 CAD most dates and now, if you want to go "direct" but not non-stop from YYZ, it's the same flight # from YYZ-YYC-NRT, but on the older 763s. Also priced high.
Just a suggestion......