"Why don't you come around to the other side of the counter?" sushi chef Junichi Onuki chirped from behind the bar. He laid down the sharp yanagi-ba knife he'd been using to slice fillets of sea bream and beckoned in a gesture of welcome.

I'd asked Onuki, owner and chef of Isana Sushi Bar in Tokyo's Nishi-Azabu district, to teach me about cutlery and other kitchen utensils in the sushi chef's toolbox. Although I'd toured many professional kitchens before, no one had ever invited me behind the bar at a sushi restaurant. After years of sitting at sushi counters as a customer, it felt both thrilling and mildly transgressive.

Onuki had arranged his workstation for me exactly as he would during dinner service. On the immaculate white cutting board sat a yanagi-ba — the long, thin knife used for slicing fish — alongside a fine-grained sharkskin wasabi grater and ceramic pots filled with homemade nikiri soy sauce and ana-tsume sauce for eel. In another jar were tweezers for removing pin bones, a perforated spoon for scooping up ikura (salmon roe), a small grater for zesting yuzu citrus, and a tiny wooden brush used to sprinkle the fragrant yuzu rind onto pieces of sashimi.