Japan may seem really, really far away. Mainly because it's really, really far away. But, right now you can go the distance for less than $500.
OK, so here's the deal: For select dates in February - May you can fly with China Eastern Airlines and go round-trip from San Francisco to Tokyo for just $484. Put in sample dates like February 8 - February 16, 2015 to find the deal. Comparable flights are going for almost $1,000 on these dates. So, like, this is literally half of what you would normally pay.
Here's a a snapshot of the available dates taken from Google Flights: