Japanese curry – kare raisu in Japanese – is unlike any “curry” you might know from south Asian countries. That is partly because of the nature of yoshoku (western-influenced) cuisine but also because it made a roundabout route to Japan, via the British Royal Navy during the Meiji Restoration, a period when India was under British colonial rule. It arrived in the form of British “C&B” curry powder, so it was considered western food, not Indian. Curry became a staple in the Japanese naval and army kitchens at the turn of the century and this in turn brought curry into homes and even into school lunches. Today, it is considered a national dish.Today, kaire raisu is considered a national dish in Japan. Photograph: Emiko DaviesJapanese curry needed to be thick enough so that it could be easily eaten with rice, with the help of a spoon. This can be achieved with a French-style roux base of butter, flour and liquid, or it can be thickened in a more Japanese style using a potato starchy slurry right at the end of cooking, which is my preference. Then there is the spice mix. Today, Japanese S&B curry powder is one of the best known, which contains 17 spices such as turmeric, coriander, fenugreek, cumin, cinnamon, fennel, ginger and star anise.In Japanese homes, it is most often made with a packet mix in the form of waxy cubes that you add to a stew of meat and vegetables. The cubes dissolve, turning the stew into a thick, fragrant, mild Japanese curry. Everyone has their favourite brand, or perhaps two favourite brands mixed together, that they pump up with “secret” ingredients – honey, nashi or prunes for sweetness, or coffee for colour and balance. My mother told me of a friend who liked to add dark chocolate. I know how well that works in a meaty stew – chocolate or cocoa is a popular addition to an age-old Tuscan wild boar stew that I love.Serves 4300g pork loin (or beef, or other protein of choice) Vegetable oil, for greasing 40g butter