If you're dead set on going to Japan around this period in time, I can suggest to you to see what you can find into South East Asia at a reasonable price and then a separate ticket over. Some thing like Manila, Kuala Lumpur, Bangkok, Hanoi etc. Also there may be random award tickets to go interesting routes like via Hawaii or Fiji (or even mainland US), India, if you don't mind a bit of extra travel time.
As the JL / NH prices, those are probably Flexible Y (or close to) those booking classes and on any given day, they are more expensive than Business class tickets normally. It's a weird thing with their tickets and how they price them. It also gives you a bunch of premium things that don't come with regular Y tickets like lounge access.