This recipe uses a lot of Chinese cabbage. There's no need to add water -- the curry will be juicy and savory thanks to the Chinese cabbage.
I had so much Chinese cabbage so I added it to dry curry.
If you don't have the spices marked with ＊ (cumin, nutmeg, coriander), you can omit them. In that case, try adding curry powder. If you like it spicy, try using spicy curry roux.
Enjoy Japanese food around the world.