Japanese, with Spanish ingredients pulled in constantly. The tasting menu opens with an oyster in ponzu, then gyoza of white prawn and pork jowl and a korokke made with Robuchon purée and wagyu cecina, before a run of nigiris and gunkans. The carta goes wider: sashimi cuts, spicy tuna and smoked toro tartares, hosomaki, uramaki and temaki, wagyu A5 from Kagoshima as a nigiri, and an angus rib roasted 72 hours to share. The crossovers are the fun part, from tempura de cocido madrileño to hamachi with sobrasada de bellota and a nigiri of akami done as a gilda.

The basement at Velázquez 136 used to be Rugantino, an Italian restaurant beloved of Madrid's jet set in the 1980s. Its interior was designed by Noldi Schreck, the Mexican architect of Russian-Swiss parents behind the Beach Club at the Marbella Club hotel and Puerto Banús, and the room is listed in the city's catalogue of commercial premises protected for their architectural interest. Ikigai kept his curved walls and white vaulted ceilings, the reason people compare it to an igloo, and the Cousi studio redid the interior as a 1980s New York apartment.

The way in is a staircase down from the street, with an aerial view of New York buildings projected onto the steps. Downstairs there's beige-and-black carpet, 1980s lamps, black lacquered furniture with chrome details, bouclé chairs, mirrors and curved niches in the walls. The sushi bar has black leather and steel seats where you can watch the nigiri being made, and a private room for eight sits behind golden curtains around an oval table.

The Menú Ikigai costs €90 and is ordered by the whole table. After the openers it runs through a string of nigiri and gunkan: sea bass with beurre blanc and wagyu cecina dust, a green tea gunkan with Japanese whisky, ikura and quail yolk, flamed salmon with Savora mustard and ají amarillo, akami done as a gilda, smoked toro tataki with avocado and pickled jalapeño, tuna tartare with bone-marrow flan, hamachi with sobrasada and apple tatin, flamed butterfish with sweet miso, and scallop with foie and eel sauce. It ends on an almond sponge with yuzu cream and a white chocolate and Sichuan pepper sauce. On the carta, the gyoza of white prawn and pork jowl and the Robuchon-purée korokke are house classics, and the tempura de cocido, duck magret from the Landes and sesame soufflé all have fans.

The cocktail list is classic in style with a section given over to Japanese whisky, served in 50 ml pours in any of four traditional ways, and there are highballs built on Japanese whisky too. The chef also hosts Ikigai Sessions, collaborative menus cooked with other chefs and restaurants.