Katsuo — Skipjack Tuna and Its Seasonal Double

Japan-wide — Kochi/Tosa Prefecture is the cultural home of katsuo tataki; Edo (Tokyo) for hatsu-katsuo culture

Katsuo (skipjack tuna, Katsuwonus pelamis) is one of Japan's most culturally resonant fish — the subject of haiku, the source of katsuobushi, and a seasonal double experience: hatsu-katsuo (first bonito, spring — April–May, leaner, more delicate, expensive for its rarity) and modori-katsuo (returning bonito, autumn — September–October, fat-laden after summer feeding in northern waters, richer and more intensely flavoured). Both are prized for tataki preparation (surface-seared over straw fire, sliced, served with ponzu, garlic, green onion, and grated ginger). The two seasons of katsuo represent Japan's dual aesthetic appreciation — the delicate first arrival of spring vs the rich abundance of autumn. In traditional Edo food culture, the first katsuo of the season was considered so auspicious that Edoites would pay extraordinary prices to be the first to eat it.

Hatsu-katsuo: lean, clean, bright with mineral notes; modori-katsuo: rich, fatty, nearly tuna-toro levels of fat — the same fish in two completely different seasonal expressions