Bringing this post to the top...
Have to admit that YOKOSO/Visit TOHOKU fare is a bargain, 5000 yen per segment and the fare is still available. On my next trip to Japan I will visit Tohoku region and I can make use out of this fare. 5000 yen per segment is less than half of JL or NH's Visit Japan fare. US$ getting bit stronger against JPY help, too.
Experience JAPAN fare on NH seems to have restricted availability where the fare may not be available on all flights, where YOKOSO/Visit TOHOKU fare looked like not as restrictive, was available on all flights choices I looked up.
I understand that YOKOSO/Visit TOHOKU fare will likely to be limited time fare, and may not be available next time I can take advantage of this fare. But glad it worked out for me on this up coming trip.