Interestingly their OPS splits are pretty much identical vs left and right (.770 vs .779), though the eye test does make it seem like they struggle against lefties. Probably just random variation or we've just had better pitching against opposing righties.
How big into baseball/Ohtani is the Japanese side of the family? My wife is half Japanese but unfortunately doesn't follow sports or know who any athletes are unless they intersect with tabloid gossip (which guys like Ohtani and Trout never will).