Today a Japanese friend and I had lunch at the new restaurant called Kansai (Buchanan Street near Sutter) that took over the building where Sushi A was located. This indeed appears to be the same restaurant that used to be located on Sacramento Street in the financial district but closed a number of years ago -- at least the logo is exactly the same.
This version of the restaurant appears to serve more as a drinking bar, sushi bar, and karaoke pub, but there are some tables in the back and they are open for lunch and dinner. There's a variety of different food offered -- sushi, sashimi, donburi, udon, teishoku, etc.
I had regular chirashi (raw fish on top of rice) for 10.95. It came with a generous salad and miso soup. It tasted fine but nothing outstanding.
My friend had the tempura udon. The tempura was served separately on a lacquer tray, which was somewhat unusual. That way the tempura won't get all soggy in the soup. My friend said the udon was Kansai style but the noodles were too mushy for her taste (a common complaint).
So this place isn't bad but it's nothing special, just like the majority of the restaurants in Japantown (exceptions: Maki and Juban).