A month or so ago, when I was visiting a friend who lives in downtown San Jose, we decided to wander and pick a place at random for supper. We ended up on Jackson Street at a place called Gombei. I've been back a few times since, and been most pleased with the results.
While I discovered later that it's one of several around the Bay (other locations in Santa Clara, Menlo Park, and Sunnyvale), the menu of the one I've visited in San Jose Japantown can be found online here- http://gombei.com/gombei_rest_-_san_jose .
First, it's cash only, so keep that in mind when you go hunting for dinner. The closest ATM is a good distance away too, so be prepared for a walk if you come up short!
Second, it's loud. If you're looking for a quiet dinner this is not the place. That doesn't bother me. Restaurants, in Asia, are places to gather, to socialize, to interact. Loud is normal. Service can be a bit terse, but it's a small spot, and the food and booze show up fast. They don't rush you, but there's a lot going on in just about every square foot of the place.
I'm not normally one to make use of on-table sauces and condiments, but they have furikake and several other Japanese diner-esque items in easy reach. That gets bonus points from me, but in the heart of Japantown I'd be rather more surprised to find the lack!
Their udon noodles were thinner and lighter than I was expecting, but the end results were excellent. Fried shrimp (not tenpura, but I like this incarnation better) was perfectly crispy, not a bit of sogginess, and the broth in the Pork Udon was intense. I also rather liked their croquettes- curried potato and onion, hot and crispy, but not so large as to fail to heat through when fried.
Poki tuna had excellent flavor from the classic soy/ginger/scallion/sesame combo, but it needed some more love- they cut the fish poorly, and I ran into some awkward connective tissue. Probably an occasional mistake, no big deal. I've done it too.
Nitty-gritty details aside, I like Gombei a fair bit, and suspect its other branches will likewise meet my approval. I'll be reviewing them when I have the occasion to drop in and try them. This is a comfortable place to kick back for a satisfying dinner- a few friends, a few beers, on a quiet street to walk off the overindulgence afterward. For a place like this, that's all you can ask for.