I had the most awesome dinner at Koi the other day with someone who was an ex-sushi chef. It made an incredible difference in my experience to order very special, not often made and less often seen sushi dishes that challenged the chef. I don't remember any of the names of the dishes, but towards the end of the night, the chefs started to send us things to try that they thought we might like. The one thing I do remember was eating a sashimi called kamachi (not hamachi) with a house ponzu sauce. It was awesome.
It might have been the amount of money we were spending, but I honestly believe that they liked the challenge and departure from the mundane rolls that they make hour after hour. We got a lot of smiles from the head chef as we left that night.
I would like to repeat this experience and was wondering, can anybody recommend some of the more special sushi/sashimi dishes that aren't typically on the menus? Thanks.