It’s not every day you see someone’s face peeking out of the belly of a bright blue skipjack bonito (katsuo). You certainly don’t expect them to wear fish-shaped headgear while wrapping dozens of sushi rolls all morning. But this was how Mai Nagamatsu, katsuobushi evangelist and proprietor of breakfast diner Katsuo Shokudo, greeted us on February 3: her head looking like a fish at sea. It was Setsubun, the first day of spring according to the old Japanese lunar calendar, itself based on the traditional Chinese calendar that divides a year into 24 solar terms. (These days, the lunar calendar is more a reminder of cultural practices and traditional markers of seasonal changes than a practical way to keep time.)