I've been to katana-ya on geary @ mason a couple of times now. Their hours are 5pm - 2am every day. From what I can remember of the menu they offer sushi, udon, ramen, and probably a bunch of other things I can't recall right now.
They offer miso, shio, and shoyu ramen (no tonkotsu, unfortunately). You can also choose a topping, but I was born to eat pork so I never have no idea what else is available other than chashu (char siu? cha siew? chashao? ch'a shu? argh! roasted pork! damn both you and your cohorts, wade-giles!).
I've tried the miso and shio ramen so far and I can positively say that it's better than most of the other places in the city. To add some context to that, the only places I like eating ramen at in SF are Suzu, Oyaji, and BY grill.
I have yet to try the sushi there, but the selection seems pretty basic and the itamae is very friendly. There were no "specials of the day" posted anywhere but they just opened 10 days ago and it may take some time for them to feel comfortable ordering anything non-standard or of unusual quality. I did get to taste a ceviche dish the itamae made and it was quite nice. I've only had Peruvian ceviche before, but I was usually a few pisco sours into it, so it's a bit difficult for me to compare... it was certainly different though. No fruit, but it had salmon, saba, tomatoes, vinegar, and onions if I'm not mistaken.
I've no idea if this place is associated with the katana-ya in el cerrito, but it is the same guy that was involved with katana-ya in the sunset, henry the VIIIth, and niko niko sushi.
Oh, and they don't have their liquor license yet, but plan on getting one soon. So it's basically BYOB for now.
Good lord, that's a lot of text.