I contacted the seller one bay and their explanation for the very low prices is that they're the manufacturer of the knives and so can sell the knives for a lot less than any other retailer. I'm not really satisfied with that answer considering Hikari is based in Japan and the reseller is based in China, but I can't find any way to contact Hikari to confirm. Still holding out on the purchase.
I've noticed in the photos of the potentially counterfeit knives that the holes drilled in the handle are very poorly finished, very rough edges. Not something I'd expect on a typically $100 knife. Part of the reason I think they might be fake.