KOYN

Restauranteur Samyukta Nair’s knack for nailing restaurant concepts is uncanny. It’s like she’s playing a game of Pokémon Go, but the prizes are global restaurant formats. She’s ticked off Indian and Chinese with Bombay Bustle, Jamavar and MiMi Mei Fair, and now she’s onto Japanese with KOYN.

Heading up her operation is chef Rhys Cattermoul whose talent for balancing authenticity with crowd-appeal is impressive. The menu is so long it’s the type to strike fear into your heart as you wonder how a kitchen can ever nail such variation. In less capable hands it might feel phoney, but here the brigade of chefs working behind a glass wall don’t skip a beat. It’s busy and crowded in the dark and moody basement dining room, but dishes fly out - handled by some of the kindest staff we’ve come across recently - and are truly masterful.

Small things don’t allow their size to denote their impact. Petite, cold piles of spinach dressed in a creamy sesame dressing put a wonderful spin on Gomaae while two single pieces of prawn tempura are so crisp and sweet they leave us with a lasting impression.

Hot off the grill, lobster arrives simply plated but richly dressed. The claw meat is packed into the head cavity with the tail meat charred and smoky, while the whole thing is doused in an umami butter. It’s gloriously decadent and fuss free, confirming our suspicion that being made to crack your own crustaceans is entirely uncouth. Other success stories include a caramelised piece of Chilean seabass lifted by herbaceous shiso salsa verde and rich pockets of wagyu beef gyoza. Everything is washed down by excellent cocktails.

As with all things that seem too good to be true; there is a catch. Prices are sky high. However, given the plum postcode and the packed dining room, the locals round here don’t seem to notice - and for the rest of us mere mortals, this makes a very special spot to try some of London’s best Japanese food.

KOYN is a modern Japanese restaurant founded by LSL Capital, the restaurant group from father-daughter duo Samyukta and Dinesh Nair that also lays claim to Michelin-starred Jamavar, MiMi Mei Fair, Bombay Bustle and Socca. Its aim is to balance ancient Japanese tradition with modernity in order to create a unique, two-fold dining experience.  

The two-story space is located just off Mayfair’s Grosvenor Square in what was formerly the US embassy. Two distinct areas of the restaurant, Midori and Magma, have been designed to reflect the two forces at play in Mount Fuji, the former representing vegetative life above and the latter an active, bubbling volcano beneath. Midori on the ground floor offers décor inspired by a Japanese garden, with plush green banquettes, iridescent shell walls, a bronze leaf mirror and a centrepiece marble sushi bar. From here, guests can order lobster tempura sushi rolls and Applewood smoked Japanese A5 Kagoshima wagyu sushi roll with asparagus, kanpyo and black truffle. 

Contrastingly, Magma on the ground floor is an immersive subterranean space housed beneath black oak ceilings. The focal point is the traditional binchotan-charcoal-fuelled robata grill, crafted from black slatted timber and rainforest marble and lined with burnt orange leather stools, from which guests are close enough to feel the heat of the flames. 

The kitchen is led by ex-Nobu chef Rhys Cattermoul who showcases the broad spectrum of Japanese cuisine through umami flavours and locally soured produce. Alongside specialist dishes for the sushi bar and robata grill, Cattermoul has created signature dishes such as steamed clams with cordycep mushrooms, yuzu sake soy, spinach and samphire, as well as red mullet tempura with yuzu kosho tozazu with homemade kombu salt. Dishes off the grill, meanwhile, include hojicha-smoked lamb marinated with spicy kuromame miso and hispi cabbage, as well as wagyu ishiyaki served on a sizzling hot stone with yakiniku sauce.