Sadly, I've ceased my sushi expeditions after getting glutened 3 times at various restaurants in a few months a couple years ago.
Whenever I see advice about eating sushi out, I dive on it, hoping I might feel confident enough to try it again. As often as we move, I'm just waiting until we have settled down in one place to really establish a relationship with a special sushi spot.
Celiebo's sushi rules (see link to video below) are good, but I believe they lack some key insights. Celiebo's only been living gluten free for a year or two, so maybe she hasn't been faced with the following:
Miso Soup- this is a questionable item at sushi shops- I found out the hard way.
Roe (little eggs on top of sushi)- from my online research, not gluten free- I found out "after the fact" :(
Sushi Rice- some of the forums say there is questionable rice vinegar (malted?) in it at some places
Cross-contamination-perhaps this is covered on her dining card (?) or maybe she assumes we will explain it to the server.
I find that sushi places use bamboo mats to roll the rolls, so they would have to put clean saran wrap on there to avoid cc. I avoid rolls.
And, aside from using clean utensils, knives, and gloves, the counter is full of residue from the ubiquitous soy sauce and tempura "crunchies" abound in these places.
Gluten free food would need to be prepared on a clean surface. After explaining this to a waiter, who translated it to the Japanese chef as I sat in front of the counter one evening, I watched in horror as he took a used dishtowel (likely full of crunchies and soy and faux crab residue from previous swipes) out of his apron and wiped off the counter and began making my food.
I gave the food to my friend. I have had much luck at many types of restaurants with steamed edamame : ) (soybeans, usually served in their pods).
Anyway, if you are lucky enough to have established a relationship with a great sushi place, I offer you a bow! Someday I will try again....
Celiebo's sushi advice