When Jangyong Hyun worked behind the impressive, semi-circular chef's counter at Kisume, I had some complaints. The omakase experience on the top floor of Chris Lucas's flashy CBD ode to Japanese cuisine, which Hyun oversaw until last year, was rife with Instagrammable moments: dry ice and foie gras and lots and lots of blowtorch action. Less apparent were the chef's more fundamental skills. Most of the sushi fish was cut by a chef in an anterior kitchen and many of the dishes seemed more reliant on flash and theatrics than simplicity. (Full disclosure: the meals at Kisume that formed this impression were ordered in 2018.)

At Sushi On, Hyun's new restaurant in Kew, simplicity is the name of the game. Staffed only by the chef and one server, and with nothing to distract but a short sake and wine list, this is dining at its most pared-back.

For $190 per person, you get one of eight seats at a spare counter in an unassuming modern room, its main design element an illuminated sign on the wall that spells out the restaurant's name. And for about three hours, Hyun feeds you course after course (18? 20? More? I admit I lost count), almost all of them a slice of raw fish, brushed with soy, atop barely warm rice.

Let's start with that rice. Hyun uses white sushi rice seasoned with red vinegar, giving it the appearance, but not the taste, of brown rice. He dry-ages most of the fish he's serving, which emphasises the flavour of the fat, and Hyun feels that the assertive acidity of red vinegar complements that fat better than traditional sushi seasoning.

For each morsel of fish, he moulds the rice in his palm, warming it slightly in the process. It is soft but textural, almost sticky but not quite, each individual grain discernible.

The meal begins with an oyster from Tasmania but, once that's done, the next two hours are dedicated to nigiri.

Hyun cuts each piece of fish in front of you, exhibiting exactly the knife skills I wish I'd witnessed at Kisume: some fish are scored with exacting, crisscross precision, while others are draped in generous slabs. You start with three types of tuna, two from different parts of the loin, the second from a leaner section that has been aged longer and is as rich and meaty as a porterhouse steak.

As much as I adore tuna, the real excitement at Sushi On lies in the variety of fish you rarely see on sushi menus. I've long wondered why our famously fabulous seafood – outside of kingfish and salmon – is hardly used by even high-end sushi chefs here.

Hyun makes a compelling case for expanding that repertoire, making beautiful use of King George whiting from Lakes Entrance, its flesh firm and sweet and mellow. Garfish, also from Lakes Entrance, is sliced in such a way that a line of silvery skin stripes the jewel-like morsel, for a lightly oily, wonderfully firm mouthful.

When Hyun does serve more standard fish, you notice the difference. His salmon is air-dried for five days, making for a more supple, velvety and deeply flavoured fish.

There are dishes that will test conservative diners. Abalone, as tender and meaty as I've ever had, is served in a sauce made from the mollusc's liver that tastes like, well, lightly metallic fish guts. It's a fairly common dish in Japan, part of a food culture that values freshness and purity but also pungency and slippery, memorable textures. I adored it and welcomed Hyun's offer of extra rice to scoop up the remaining sauce. But if your idea of adventurous eating begins and ends with clean-cut raw fish, there will be challenges at Sushi On.

Regardless, I encourage you to step up to this particular challenge. Sushi in Australia is improving at an astounding rate right now, thanks largely to chefs such as Hyun who trust that diners are ready for a wider variety of fish, and a focus on technique over theatrics.

I'm so glad to see this aspect of the chef, who is helping to move us in a more considered, superior, intensely pleasurable direction.

Vibe: Sparse storefront with a simple sushi counter

Go-to dish: King George whiting nigiri

Drinks: Short but quality sake list, plus a few wine and beer options

Cost: $190 per person omakase (Sunday surcharge applies), excluding drinks

This review was originally published in Good Weekend magazine