I was talking about cash fares, as an example of blocking that happens even for tickets that should have a lot more availability than redemption. I'm not watching JAL redemption tickets enough to know their release schedule but I suspect they release the seats far closer than 360 days away at peak holiday times based on a few comments, but it may be a random release at a point during the year to stimulate sales.

BA and CX should have the same rewards availability for JAL.

As it sounds like you're flexible, personally I'd be choosing flights say six months out on random weekdays to get your dream of 2 JAL seats, or go for cathay (they do have more availability for Asiamiles, not sure if that will be enough for East Coast business of course). Or, and it's a worse airline, fly with BA and then you can definitely get seats 355 days in advance, though you'd need to be calling their call centre at midnight (GMT) with Avios?
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Overall it just sounds like you need to keep checking dates. I wouldn't be suggesting buying an economy ticket unless you really do have certain dates in mind, but the chances are high that you'd be taking that flight.