Restaurant competition in Soho is as fierce as anywhere in the country, especially for those sites due south of Soho Square – every lunchtime you’re doing battle with the likes of Barrafina, Quo Vadis, Freak Scene, The French House and countless other fantastic restaurants. Koya may seem a little diminutive in comparison to some of those, but the ever-present queue out of the door suggests that Londoners can’t get enough of Shuko Oda’s restorative Japanese cooking. Ten years since it first appeared on Frith Street, Koya is as popular as ever.

The food at Koya is built around two Japanese staples – udon noodles and dashi. ‘Udon is like fast food in Japan,’ explains Shuko. ‘It’s rough and rustic, whereas other noodles like soba are a bit more refined and particular. You can eat it every day.’ And people do, in their droves. The restaurant has a homely feel to it, despite its position in the beating heart of Soho. A long counter sprawls from the front of the restaurant to the back, and chefs busy themselves with big pots of broth, a raging hot grill and a steady stream of tempura prawns coming out of the deep-fryer.

The menu – largely udon and broth-based, but also featuring some rice dishes and other small plates – is only part of the experience at Koya. Three specials boards greet you as you walk in – an ever changing list of Koya’s more experimental dishes, including things like kombu-cured brill with rhubarb and yuzu oil, agedashi tofu with sprouting broccoli and grilled venison saddle with grilled and pickled radicchio.

The drinks offering is compact but perfectly suited to the food – alongside Japanese beers like Kirin, you can order sake, shōchū (Japanese distilled wine) and soft drinks.