The big 3 U.S. majors – American, Delta and United – and others – ANA, Air China – continue to offer very low fares to Japan…as low as $435 round-trip.
In the current round of fare cuts, Delta started and then was matched by United and American. A couple of dozen U.S. cities are included in the fare war.
If you have ever wanted to visit Japan, this is a very inexpensive time to do so. And you will receive some frequent-flyer miles (varies with the airline).