Yep, we have soy sauce (and gluten free soy sauce), and wasabi (well, the fake wasabi that's mostly horseradish and green food colour), sushi rice, miso, mirin, nori, sake, canned red bean and tofu. Mochiko, umeboshi, bonito, matcha powder and dashi are harder to find but there are mail order places that sell them- and Amazon- along with readymade furikake and a variety of dried seaweed. No idea if anyone does natto. Japanese ingredients that can't be packaged and stored for a while don't come in such variety. I might have to try using seaweed instead of soy sauce (I'll probably already have eaten any pickles I made! I like making pickled carrots cut to look like tiny goldfish)
Mustard, black pepper, and whatever herbs will go best almost always go into any stew or casserole I make, plus a little paprika unless it's fish, maybe a pinch of chilli or ginger- I'll generally fry chopped onion (maybe with garlic and/or finely-chopped chorizo sausage) for a base, then brown any meat that's going in, add stock or wine/beer/cider (or maybe milk and cream if it's fish) and chopped veg, perhaps a spoonful of condensed tomato puree for red meat, whatever spices, then let it simmer for an hour or three, tasting near the end and adding herbs and whatever else it needs to balance the flavours, like a squirt of lemon juice or a dash of soy sauce. If there's no potato in it I might add rice for the last half hour. The ingredients are whatever I have, so maybe what looks nice or what's in season or what we need to use up or what was on sale or what was in the freezer, as long as it will go together okay. It was more fun when I still had the old garden, because I grew vegetables and herbs. I've just got to the top of the list for an allotment now (=community garden plot?), so as of the start of this month I have somewhere to grow things again! I like to use parsley, bay leaf and thyme with beef (maybe with a stick of cinnamon), rosemary and thyme with lamb (maybe with lemon as well but I'm not a fan of mint with lamb), tarragon and parsley with fish- perhaps with nutmeg if I used milk rather than stock- maybe oregano and basil for a dish with tomato, juniper with venison or cabbage. If I want to get more adventurous I've got about 40 herbs and spices to choose from.
I also like do do North African dishes, Japanese dishes, Indian dishes, food from medieval Europe (which is a lot nicer than many people assume), seafood and anything I haven't tried before, especially (sorry, vegetarians) unusual meat (I've tried alligator, kangaroo, ostrich, hare, water buffalo, bison, springbok, camel, goat, zebra, ants and scorpion). Oh, and I like making cakes and biscuits (cookies). My Christmas present to my nieces and nephews was making stained glass window biscuits with them.