Amongst the annals of Japan’s rich food history, the creation of the konbini-staple katsu sando is, perhaps, one of the most interesting nuggets to be chronicled. It’s said that the first katsu sando was created in the 1930s at a tonkatsu shop in Ueno, at the time a hanamachi or ‘flower town’ – a district where geishas lived and worked. When, on a whim, the manager of the shop sandwiched a pork cutlet between two pieces of bread, a bolt of inspiration struck. Soon after, the dish became a popular lunch item for the local geishas, who could eat the crust-less creation without smearing their lipstick.

While this crucial piece of sandwich history isn’t what inspired Chewie and Tze-Huei ‘TH’ Choo to make sandos a key fixture of their brand-new Fortitude Valley cafe Supernova, the item’s humble beginnings – and the understated simplicity of its original rendition – resonated with the brothers.

“I’ve always wanted to do a Japanese concept, but trimmed down to a specific combo of sandos and soba,” TH tells us. “When the cafe opportunity came along, I said to my brother, ‘Hey, why don’t we do something a bit different that’s not egg and bacon – let’s do Japanese’. We want to take it back to the original, like how it was founded in Japan in the 1930s – sauce, meat and bread, and that’s it.”

Supernova, which opened to the public in mid-May at the base of The Eminence on McLachlan Street, sees the duo stepping away from the eye-popping maximalism of the sandwiches at their viral-hit croque dispensary James & Antler. This time around, the duo is drawing inspiration from Japan’s exacting approach to the culinary arts, employing a minimal presentation style that lets the cafe’s high-end ingredients speak for themselves.

“We wanted to veer away from what’s very trendy at the moment – a lot of fillings and the giant-looking sandos,” says TH. “That’s what [the concept] is about – precision, the little things that matter. Supernova is about the ingredients, the spirit of the product and how we showcase it.”

Modern and roomy, with plenty of natural light pouring through, Supernova’s similarly crisp and minimal set-up perfectly aligns with TH and Chewie’s no-fuss Japanese inspirations. Though the space was already fully furnished, the team has looked to pull back on some of the corporate aesthetics by adding more colour (via vivid Takashi Murakami-style prints) and installing a vinyl-record player on the coffee counter, making the venue feel less like a lobby cafe and more of a hip hideaway.

Meanwhile, Supernova’s offering – designed by chef Zach Walker – makes deft use of top-notch produce, delivering big on flavour while managing to keep presentation simple.

“Zach’s approach to food has always been about simple cooking and letting the produce shine,” says TH. “So, what we really wanted to showcase in Supernova – the simplicity of Japanese food – plays into Zach’s hands, because that’s how he cooks anyway.”

All of Supernova’s sandos are made with Japanese milk bread and house-made sweet barbecue sauce, and are accompanied by a saucer of shoyu-based barbecue dipping sauce and pickled ginger. Fillings include classic chicken and pork katsu, black Angus katsu, spicy tuna and tamago (Japanese omelette with mayo). Though all of these options are wrought from choice components, diners seeking an ultra-premium option should look to the SUPER-nova Sando – a luxe lunch item boasting a Tajima A4 wagyu striploin, house-made barbecue-miso demi glaze, caviar and gold leaf.

Sharing equal emphasis with the sandos is Supernova’s suite of buckwheat soba noodle dishes – a dish that TH believes is an underrated member of the noodle pantheon. “Ramen is everywhere, but not a lot of cafes in Brisbane do soba, so we want to bring it to the market and showcase it more so with a cafe style,” explains TH.

Supernova’s four-strong selection of soba-based dishes includes noodles topped with the likes of wagyu tataki and oyster mushroom, tuna sashimi with radish and nori, crispy skin barramundi with yuzu dashi, and tempura vegetables.

Beyond sandos and soba, Supernova’s menu also features Japanese-inspired breakfast dishes like thick honey toast topped with whipped mascarpone, syrup and autumn fruits, spam katsu with folded eggs, and pan-fried potato mochi with aged-cheddar sauce and hot-honey-soy boiled eggs. Guests will also be able to nibble on cabinet items like kare pan (also known as curry bread, a grab-and-go staple of fried bread with a hearty curry filling) or flat croissants with a strawberry and cream or double-choc coating.

On the coffee front, TH and Chewie have once again partnered with Kasa Coffee, but this time the team is using the roaster’s Illusion blend, which won bronze in the Milk Based category in last year’s Golden Bean awards. Beyond coffee, Supernova also boasts a range of matcha- and hojicha-based beverages, including hojicha with kuromitsu (brown sugar syrup) and oat milk, strawberry matcha with Yakult and sparkling matcha grapefruit. Matcha soft-serve ice-cream, matcha-misu and strawberry cake cans are also on hand for a perfect sweet finish.

While there’s already a lot to digest on Supernova’s stacked menu, TH and Chewie aren’t quite finished. Expect the cafe to broaden its menu with other Japanese-inspired specialties in the future.