It would be easy to be seduced by the truffle, the caviar, the foie gras. At Warabi, the Japanese omakase restaurant at Melbourne's new W Hotel, such recognisable luxuries are plentiful. There's gold leaf on the matcha tart for dessert, and dollops of oscietra caviar on the sea urchin – which is itself sitting on some of the fattiest Japanese wagyu you're ever likely to have encountered. These things may help to justify the hefty price tag of the meal ($245 a person, sans drinks) but they are not the primary reason to visit.

The real star of the show at Warabi is the dashi. Dashi, the umami-rich broth made from kombu, is the specialty of Jun Oya (pictured), one of the chefs at Warabi (his official title: Specialty Japanese Chef), and it shows up in many of the dishes that are passed across the counter.

It first makes an appearance in jelly form, cloaking a jumble of baby abalone and barely cooked scallops, lending the bouncy and sweet seafood a delicate savoury perfume. Later, it gives astonishing depth to tamago – Japanese rolled omelette.

During the sushi course, a small cup of miso soup is served, made using a base of that magical dashi as well as three kinds of miso. At the bottom of the cup, a sesame-flavoured blob of house-made tofu comes as a textural surprise: lightly stretchy, like mochi, it tastes like tahini. It would not be an exaggeration to say that this small serving of soup and tofu was probably the best thing I've consumed in months.

Warabi, which is the first restaurant outside of Asia for Tokyo-based company Wa Creations, advertises itself as a kappo-style restaurant, although the meaning of "kappo" is hard to decipher. The literal translation of the word, according to the quiet but enthusiastic servers at Warabi, is "cut and cook", and it's been used around the world to describe various kinds of tasting menus.

But if you look to Japan, most definitions describe a less formal way of eating, wherein the meal is created based on the conversation between chef and guest. Regardless, the important factor is that the food is made in front of the customer, and that there's an element of showmanship to the experience.

It would not be an exaggeration to say that this small serving of soup and tofu was probably the best thing I've consumed in months.

Warabi serves what is undoubtedly some of the best sushi and sashimi in the city, with the chefs' knife and rice skills on beautiful display as they prepare the fish.

I was especially thrilled to see local seafood varieties rarely used in Melbourne sushi restaurants – sea perch, imperador, King George whiting – given their due on the sushi and sashimi plates.

The finale to the sushi course, a wide roll made with a truly outrageous amount of Japanese otoro (tuna belly), was one of the most decadent mouthfuls I've encountered, but I wasn't exactly happy about eating it. Not because it wasn't delicious – it was, unabashedly so – but because I wish sustainability were higher on the list of priorities for this (and other) restaurants. Bluefin tuna is critically endangered, and I generally avoid it; here it comes as part of the package.

If anything, I found all the luxury ingredients to be a bit distracting. That lovely tamago dish, bathed in Oya's gorgeous dashi, didn't need the black truffle shot through it to compete with the delicate flavours of snow crab and eel.

I couldn't taste the sea urchin hiding between the gloriously buttery wagyu and the caviar topping: all that richness obliterated the elegance of the seafood, although the textural combination was admittedly dreamy.

The best bites of food during an evening at Warabi were the simplest: the way King George whiting shines in its raw form, draped across barely warm sushi rice; the pop of salmon roe atop perfectly yielding soba noodles; the comfort of that deep, rich miso broth.

For a corporate hotel group and an international restaurant company to come up with something so singular is an achievement. To do it with something as personal and perfect as Oya's dashi is a revelation.

Vibe: Sleek and minimalistic

Go-to dish: Baby abalone and scallops in dashi

Drinks: Impressive wine and sake list, mostly very expensive though I managed to find a great sake for $135 a bottle. Drinks pairing available for $180 per person

Cost: $245 tasting menu, excluding drinks

This review was originally published in Good Weekend magazine