Originally Posted by
moondog
75k isn't enough to do J one way (55k) and Y the other (35k).
Therefore, I suggest you focus on flying F (62.5k) in one direction, and figuring out something else (e.g. other miles or discounted ticket) in the reverse.
Personally, I would use the F segment on JL ex-TYO (surprisingly good airline food).
Japan is Asia 1, which requires 50K in J and 25K off-peak in Y. What you referenced is a mix of Asia 1 (in F) and Asia 2 (in J and Y) rates.