Sweet mushroom in soba with noodles

Hi guys, Just came back from a week and a half in japan and I must now find out what that sweet tasting mushroom was in the soba that I ordered. Was kind of dark..and very sweet and the best mushroom I have ever tasted. It was in the soba udon soup along with a fishcake and spiral tofu roll I think. Any idea's what its called? After a bit of research I thought it may be shiitake but the shiitake mushrooms I've had in Australia look and taste nothing like that Japans. This website shows various mushrooms and the shiitake one here http://www.foodsubs.com/Mushroom.html kind of looks like it. Any thoughts?
Thanks
Michael

I think it was a shiitake. They can become very sweet, especially the dried shiitake that will soak up the sweet taste of the liquids you soak them in. And I think it is the most popular mushroom to be put into soba dishes.