This is from Kentaro Kobayashi's book Bento Love. I make this for my lunchbox quite often, as it's so easy to throw together. The combination of the curry and rice vinegar makes a very flavorful marinade, which doesn't go bland being served at room temp, which is a bonus when you don't have the facilities to heat up your lunch! Any curry powder will do in this recipe, if you like the hot stuff, go for it! Note- this is meant to be a side dish. If you want to enjoy this as the main (or only) item in your lunch, increase the quantities to suit your appetite.