The Japanese have taken curry and made it their own dish. I read about Nakamuraya being quite an institution in Shinjuku. They take up almost an entire building of several floors, each with a unique specialty ranging from Indian to Italian.
The "Indo-Kare" or Indian Curry (¥1,470) is the flagship dish served at Repas on the second floor. It's rich, deeply spiced but not overpowering. And interestingly, it has a strong heat that's not immediately apparent but emerges after a few mouthfuls. Wonderful curry served with pickles and chutney. However, I found the sticky Japanese short-grain rice not as appropriate as basmati rice for this dish.
Repas at Nakamuraya also serves European style stews. We went for a Wagyu Hayashi Rice (¥1,785) - beef, mushrooms, carrots and onions in a thick, demi-glace sauce. Nice and robust too, although we both preferred the curry.
2F, 3-26-13 Shinjuku, Shinjuku-ku, Tokyo
Open daily 11am to 10pm