United and ANA have round-trip flights from Los Angeles (LAX) to Tokyo or Okinawa, Sapporo, or Fukuoka (OKA/CTS/FUK) for $615-$620. Flights October to May.
Note: Some small OTAs on SkyScanner have this for $561. If you plan on booking there, beware of any site that charges a fee to cancel a ticket within the 24-hour “free” period. Use unknown booking sites at your own risk.