Eating with the seasons is at the heart of Japanese cuisine. Each fish has its moment, the time when its flesh reaches its best. In early summer, that moment belongs to katsuo: a bright, clean fish that signals the arrival of warm days better than any calendar.
What Katsuo Is
Katsuo is skipjack bonito, a cousin of tuna, recognizable by its deep red flesh. Lean in early summer, it has a clean, almost iron-like flavour, very different from the roundness of fatty tuna. It is a fish that does not cheat: its quality is tasted at once.
It is also known in another form: dried, smoked, and shaved into flakes, it becomes katsuobushi, the soul of the dashi stock that flavours much of Japanese cooking. The same bonito feeds two worlds, the bright sashimi and the foundation of the kitchen.
The Season of the First Bonito
Bonito migrate with the warm currents, moving up along Japan as the sea warms. Their first appearance of the year, in early summer, has a name: hatsu-gatsuo, the first bonito. Prized for its clean, lean flesh, it is awaited each year as a marker of the season.
A second season returns in fall, modori-gatsuo, with a fattier, rounder fish. Two moments, two personalities for the same fish. Serving katsuo at the right time means respecting this natural calendar rather than ignoring it.
The seasonality of fish in JapanWhy each fish has its moment in the year.Katsuo at Aji's Counter
At the counter, the chef often works katsuo as tataki. The piece is seared for a few seconds over flame: the surface caramelizes, a smoky aroma is released, and the core stays raw and fresh. That contrast, warm crust and bright flesh, is the whole point of the preparation.
It is then served with what wakes its clean flavour: fresh ginger, slivered green onion, sometimes a little garlic or a dash of ponzu. Nothing that masks, everything that underlines. At the four-seat counter, you watch the flame pass over the piece before it reaches your plate.
Pairings and BYOB
Katsuo's clean flesh and light smoke call for freshness: a crisp, clean white, or a sake served cold. If you bring your own wine, a taut mineral white accompanies the piece beautifully without dominating it. BYOB at Aji is 5$ per table.
In which season is the first bonito, hatsu-gatsuo, celebrated?
Asking for the Seasonal Piece
Katsuo is a seasonal piece: it is not always on the menu. It appears on the omakase when early-summer deliveries allow. The best way to taste it is simple: ask at the counter what is at its best that evening. The answer follows the seasons, and that is the whole spirit of a kitchen that lives by the rhythm of the sea.
- 1Katsuo, or bonito, is a signature fish of early summer.
- 2Hatsu-gatsuo, the year's first bonito, is celebrated for its clean flesh.
- 3The chef often works it as tataki, flame-seared, raw at the core.
- 4It is a seasonal piece: available depending on deliveries.
- 5Ideal pairing: a crisp white or cool sake. BYOB at 5$ per table.
Katsuo tells a whole season on its own. Tasting it in early summer is eating the precise moment when the sea warms and the fish reaches its clean peak. Ask for it at the counter, and let the season decide.
Book your table and ask for the seasonal piece at the counter.
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