Yes, Sepia is still with us. No, it hasn't moved to Melbourne yet. Yes, it is still brilliant.

And here's the news – it will be brilliant for another seven months, until its last service on December 15. But it's not the Sepia you thought you knew, the one that opened nine years ago with a sophisticated New York vibe and a contemporary post-Tetsuya menu focussed on seafood from co-owner George Costi.

"There are no rules anymore," says chef and co-owner Martin Benn. Some chefs might find an imminent closing date restrictive, but Benn feels liberated.

So instead of winding up with a retrospective menu revisiting old favourites, he and partner Vicki Wild have just introduced a highly evolved menu of small, artfully presented dishes that change frequently – sometimes daily – according to the ever-changing seasons. "It's my own style of kaiseki," says Benn.

It begins with five small but striking one-bite dishes that are as polished as multi-faceted jewels. A glossy orb of saikou salmon with smoked roe and sudachi (citrus), pure culinary bling. Tempura oba leaf dotted with smoked prawn mayo. A bouquet of raw bonito with dashi cream and purple linaria flowers. A dark tower of tuna and yuzu kosho (fermented chilli and yuzu) wrapped in kombu. And a dramatically black-and-white striped all-sort of egg white tofu and smoked eggplant dashi gel. This kitchen goes to a lot of trouble so we can have a lot of fun.

Ensuing courses, some grouped dishes and some single, include char-grilled black lip abalone with jamon cream, mushroom and lardo; a masterly cross-section of scampi roll wrapped in white kombu; and a pure white marshmallow of coconut topped with Sterling caviar. Who on earth tops coconut marshmallow with caviar?

The dishes keep flowing, towards and through us. Velvety bone marrow with cauliflower and wasabi. Sansho-roasted duck, disarmingly topped with sheaths of pickled pink lady apple. David Blackmore wagyu karubi (a cut from near the brisket) mixed with sushi rice and shishito pepper emulsion topped with crisp tempura'd shungiku leaves.

The cheese course ($30, to share) looks like a creation from famed Parisian patissier Pierre Herme. L'Artisan's washed-rind mountain man is aerated using a syphon gun, nitrous oxide and a vacuum chamber, the bubbles caught and suspended in gel by a blast freezer, topped with diced apple and a crisp tuile lid made of sobacha (roasted buckwheat tea). It's like eating a perfect round of cheese-flavoured Aero bar.

To follow, a salute to Japan with a blood-red disc of iced blood plum floating like a rising sun above raspberries and salted white chocolate cream.

There are a number of things Sydney will miss about Sepia. How you are welcomed into the restaurant, and farewelled as you leave. The high personality count on the floor – Vicki Wild, sommelier Rodney Setter, manager Benjamin Brown. The precision with which the restaurant works; every detail accounted for. The consultative, diagnostic approach to service. The way Setter makes the most esoteric wine seem like a perfectly natural choice. And, of course, the absolute and utter beauty and creativity of the food.

Benn says he has plenty in store for Melbourne, but "it won't be this".

You have seven months, Sydney, to see just how good "this" is.

The low-down

Cost $245 a head for a 19-dish, 12-course tasting menu, plus drinks.

Vegetarian Happy to do a vegetarian (not vegan) menu with 24 hours' notice.

Drinks Care for nothing but champagne matched to your food? Or sake, or even tea? Rodney Setter raises the role of sommelier to an art form in a seamless presentation of fine wine, with plenty of adventures to be had by the glass and post-dinner.

Go-to dish The sakizuke of five small appetisers.

Pro tip The menu is the same in the New York-style bar, which takes walk-ins.

Terry Durack is chief restaurant critic for The Sydney Morning Herald and senior reviewer for the Good Food Guide. This rating is based on the Good Food Guide scoring system.