blazing tartan
it could be a store in the city where chefs could buy items for their secret menu, it could cost around the same price as the sushi merchant. for example: they could buy strawberry milk to put in their secret menu for 1000 sushi rolls, ramen/tonkatsu for 1500
another idea is js for customers to experience one of those convenience stores, buy your items and you can sit down to eat
i can see how this would be a lot of work tho and but it would be sooo cool
molten lintel
this may take away from the restaurant so I dont think they'll add this
sour mural
this may take away from the restaurant so I dont think they'll add this
this. They also have takeout and a sushi conveyor if you don’t want to be fully served, prob not adding this.
supple talon
I see where you're going with this but I don't think it's a good idea to add more ways to obtain secret recipes, they're meant to be rare.
unreal viper
Awesome idea, but lots of people have lots of sushi and it would make it less fun to obtain secret recipes. The Korean convenience would let you buys drinks food etc for sushi as you said but it wouldn’t be secret you can buy it over and over. (Imo.)