Koj, 3 Regent Street, Cheltenham GL50 1HE (01242 580 455). Meal for two, including drinks and service: £60

As the current series of MasterChef roars along, full of shout and John Torode’s eye rolling and sauces spread with the backs of spoons, consider for a moment the lot of those who will make it to the final. For weeks, they will have been allowed to indulge in the one thing that makes them happy: cooking. What’s more, by making it to the last three, they will have been told they’re good at it. One of them wins. Two of them are runners-up and announce they couldn’t be happier for the one who beat them, because the narrative demands a quiet emotional lie or two.

And then? It’s not easy. The title, as hard won and brilliant as it is – yes I’m a regular judge; yes I’m biased – does not come with an immediate career path. Some, like Thomasina Miers, seem born to the life entrepreneurial. She appeared to waft from winner to Mexican restaurant chain Wahaca as if it were inevitable (though doubtless it took sweat). Others give up great careers and start again. I was mystified initially by 2008 winner James Nathan who had spent years training to be a barrister, only to throw it all up for a lowly job in the brigade at Le Gavroche. It’s worked for him; within a few years he was Rick Stein’s head chef in Padstow and now heads the kitchen at the St Enodoc Hotel in Rock.

Some set up supper clubs. Some do “consultancy”, which covers a multitude of sins. Some loiter at food world parties full of hidden shallows, canapéd to the gills and then simply disappear, seemingly air-kissed out of existence. Obviously, most of them would like to open their own restaurant, but it takes money. For every Tim Anderson, who found backing for his ramen shop Nanban in Brixton, there are others who can’t get there. I remember the desperate sadness of one finalist who told me they wanted to remortgage their house to do so, but that they had been vetoed by their family.

Andrew Kojima, a finalist in 2012, has played the long game, whether by necessity or design. After MasterChef he gave up the career in the city and worked his way through stints both short and less so at everywhere from the Ledbury to Le Gavroche to Dinner by Heston Blumenthal. He worked as a private chef and did pop-ups. Only now, courtesy of some crowdfunded dosh, has he opened his own place, an Asian café in Cheltenham drawing on his half-Japanese heritage.

After all this time, you might presume fireworks, but there’s something cheerfully low key about Koj, located in a Georgian terrace off the main shopping drag. The cultural signifiers lie in the huge image of Pikachu on one wall – ask your kids – and multiple Japanese brand logos on the other. The main grazing dishes cost £8. There’s a list of hirata buns at £4 to £6, and sides at a couple of quid each. The young teens lending us their company fall in love with small bowls of buttery garlic rice at £2 a pop, the surface decorated with a tangle of spring onions, the pearly white grains sticky but separate. We send for more.

As we do for the Koj Fried Chicken – work out the initials yourself – which is halfway between the softness of American southern fried, and the full-on crunch of Japanese karaage. Sesame flavoured mayo sends it happily on its way. But the real gems are far more subtle. Three fillets of lemon sole, curled around themselves into cones, like illustrations from a Good Housekeeping cookery book circa 1978, are precisely steamed and then served with a butter punched up with ground-down seaweed. It’s both delicate and, for that £8 price tag, extremely good value.

The kitchen’s light touch is even more pronounced with the vegetables. It is April and we are not far from the Vale of Evesham so, of course, there are asparagus: crunchy thumb-thick speers, deep green and sliced on the vertical, then dressed with the high notes of lemon and the darker, warmer thud of barley miso. Purple sprouting broccoli, cooked just enough to take the edge off, comes bathed in garlic, chilli oil and lots of fresh red chilli. It’s a bowl of vigour and class.

Marinated and seared sliced beef comes on a sprightly salad of ginger, shiso and daikon for extra crunch. The most ostentatious of the dishes is an okonomiyaki, a Japanese omelette of fried squid, piled with curly flakes of bonito (dried tuna), sliced spring onions, seaweed and mayo spun through with sriracha. It’s a whole lot of textures and flavours on one plate: the bounce of the squid, the crunch of the fried eggs, the slipperiness of the sauces, all overlaid by a pronounced fishiness from the bonito. You either get it or you don’t. I do. My companions don’t.

A list of hirata buns is a weak point. The buns themselves are less fluffy white pillows than deflated duvets. They should be forced to fold over against their will. These are engineered for that fold. The best of the lot is filled with a deep fried soft shell crab with a spicy take on Marie Rose sauce. Naturally, one filled with more of their KFC is good on texture. What’s not to like? Both a pulled pork and a confit duck are less successful. The sauces are too sweet. The buns fall apart under all that softness and moisture.

Desserts are just a little, but not too much at only £3 each. There’s a dinky pot of posset flavoured with yuzu, and a tea cup-sized portion of sticky toffee pudding with a caramel sauce made with miso, bringing a little welcome salt to the caramel. The wine list is tiny, with just one choice each at £18 or £30 for red or white, but there’s a long list of Japanese beers, which go beyond the banal of Asahi and Sapporo to Hitachino Nest Red Rice Ale and Coedo Shikkoku Black Lager. No, I have no idea what they’re like; I just enjoyed typing the names.

Koj may have his nickname above the door but tonight he’s not behind it, which is a ballsy move for a restaurant that’s been open only four weeks. Apparently, he has a dinner to cook elsewhere. Not that it shows. It’s a slick and confident operation, run by a team which knows what it’s doing. Andrew Kojima has indeed played the long game post MasterChef. So far, it’s paid off.

Jay’s news bites

• Half an hour’s drive from Cheltenham, in a repurposed petrol station at Frampton Mansell is the sweetly named Jolly Nice. It’s a farm shop selling products bespoke, organic and pricey. More importantly, there’s an open kitchen dispensing seriously good hamburgers, including one made with Kentucky Fried Pheasant. Place your order, then take your pager to the heated yurts. They’ll give you a buzz, as will the burgers (harrietsjollynice.co.uk).
  
• The proportion of us eating breakfast out of the home has dropped by almost 75% in the past two years, from 15% in 2015 to 4% now, according to a survey by purchasing company Beacon. The estimated daily spend has also dropped dramatically from £76m to £20m. Either we’re eating breakfast at home or skipping it altogether.
  
• Yo! Sushi, whose USP is the conveyor belt of dishes, is opening a new branch at Croydon Boxpark… only without the conveyor belt. It will be serving ‘Japanese street food’, handed to diners by real people. It will never catch on.
  

Jay Rayner’s new book, The Ten (Food) Commandments, is out now (£6, Penguin). To order a copy for £5.10, go to bookshop.theguardian.com

Email Jay at jay.rayner@observer.co.uk or follow him on Twitter @jayrayner1