Five Japanese ingredients that go well in pasta sauce

You may not know this, but Italian food is reasonably popular in Japan. You can find Italian restaurants at various price ranges, you can find pasta in every super market (although you may have a limited selection of noodles) and Japan even has its own Italian-inspired pasta dishes. However, while people here will substitute button mushrooms for other local varieties and do interesting things with pasta like add tobasco sauce to pasta, it doesn't seem like people mix ingredients that are traditional to Japanese cooking into their pasta sauces very often.

This is something that daid and I have been doing at home though and we've had largely positive results. For the most part, we've just been using diced tomatoes as the base for our sauces because it's generally easier to find and cheaper than pasta sauce, but lately we've also tried making some Alfredo sauce (which is surprisingly easy). So I present you with a list of five ingredients that go in pasta sauces reasonably well.