Curry powder is a blend of different spices, used to cook curry easily. The blend primarily contains turmeric, coriander, cumin, and pepper, which are grounded into a powder, roasted, mixed, then aged. The contents may differ depending on the manufacturer.
Curry powder can be used in various Japanese fusion dishes such as dry curry (Japanese keema curry), curried pilaf, or curry doria (Japanese curry rice gratin). Also, you can use it to simply flavor meat or fish dishes. It can be used to make curry roux by cooking the curry powder together with flour in oil.