Well if anyone had the details, it wouldn't be exclusive, would it... Yasuda works with various suppliers. Also, lots of sushiya have fish flown from Japan. So I'm sure Kuruma's tuna is from his source in Japan, secret or exclusive or not.... ← If anyone here is eating at Kuruma anytime soon, if you could ask where the tuna came from (geographically) it would be interesting to find out, as I didn't think the best bluefin was coming from Japanese waters. The best stuff seems to be coming from Spain as of late. I know there had been efforts to farm bluefin in Japan so an exclusive Japanese fishery could be the explanation, but then again, it's not very likely a place like Kuruma would opt for farmed over wild when it comes to bluefin for toro.