This recipe goes back to the roots of Japanese curry; it's almost a rich beef stew. Beef symbolized the opening of the country to outside influences in Meiji Era Japan. Leftover curry freezes well, but take out the potatoes or they will turn into mush.
Japanese curry mixes are labeled with their level of spice. Amakuchi is quite sweet,chūkara is medium and karakuchi is hot. I usually use a chūkara mix and add some red chili powder at the end if I think it needs more heat.
Stewing beef such as chuck (neck/shoulder) cut into 1 cm pieces — 500 g
Vegetable oil — 2 Tbsp
Butter — 2 Tbsp
Large onions — 5, thinly sliced
Ginger — 1 large piece, finely chopped
Garlic — 3 cloves, finely chopped
Medium carrots — 3, sliced 5 cm thick
Medium potatoes — 4, peeled and cut into 1.5 cm pieces
Water — 1.5 liters plus ½ cup
Dried bay leaves — 2
Commercial curry mix — 240g (1 large packet or 2 small packets)
Red chili powder (optional)
Plain steamed rice
Heat 1 Tbsp of oil in a heavy-bottomed pan over high heat and add the beef. Sauté until well browned. Take the meat out and set aside. Add the rest of the oil and the butter to the pan; add the onion, garlic and ginger. Sauté over medium-low heat until the onion has lightly browned. Turn the heat up to high and add the carrots, potatoes and beef. Sauté briefly, then add 1.5 liters of water and the bay leaves. When the pot starts to boil, lower the heat to a gentle simmer.
20 minutes in, remove the potatoes with a slotted spoon or spatula (this prevents the potatoes from disintegrating). Continue simmering the sauce until the meat is falling-apart tender, an hour or more.
Remove the pot from the heat. Add ½ cup of water to cool down the sauce, then add the curry mix, broken into small chunks. Stir until the mix has melted completely. Add the cooked potatoes back and reheat the sauce over a medium-low heat — do not let it boil. Add a little red chili powder to taste if needed.
Put some hot steamed rice on one half of a shallow bowl; pour the curry on the other half. Serve with fukujinzuke (a chopped vegetable pickle), rakkyo (pickled shallots), grated cheese or a raw or boiled egg.