Depending on what the OP is hoping to get out of an FFP, consideration might be given to a
different frequent-flyer program. For example, United's MileagePlus program has affiliated credit cards in Japan:
https://www.united.com/en/us/fly/mil...-partners.html
(United and ANA are both Star Alliance members. MileagePlus miles can be redeemed for flights on any Star Alliance carrier -- including ANA. Cash-paid ANA flights can be credited to MileagePlus.)