Relied on this Izakaya multiple times during our trip. You order online using your phone via a table specific qr code. Phone translation made it easy. There is an allergen filter that allows you to limit the menu to items that do not contain wheat. I ate here 3 times, as well as a few other Tengu locations and did not get sick. (For context, when I have accidentally ingested gluten during travel, I'm puking 90 minutes later, so no reaction is a pretty good indicator).
My go to items are:
Skewers with salt (no sauce)
-chicken thigh
-chicken and scallion
-pork and shiso leaf
-avocado with butter
Tofu with ginger, scallion and salt
Tuna and avocado salad (this has mayo and mustard, I've had no issue, but use your own judgement)
Salt pickled cucumber
Edamame
Ume (plum wine) sour
— Somewhat
— Most/All
— Excellent