I haven't eaten at the Westlake location, but the Harbor Steps location is my favorite unpretentious sushi place downtown. The happy hour specials are good, the service is attentive and very helpful, the sushi is as good as I've had in Seattle, but give everything else on the menu a try also. The tempura is the best I've had anywhere, ever. The yakitori skewers are a good option for folks who shy away from the raw stuff. Last time I was there, a group of half a dozen Japanese women were having a late lunch. This has become my new rule of thumb in seeking out good, authentic ethnic food. If the people who should know are eating there, it must be good.
As a postscript, you are likely to see some sumo on TV. And you really should try a shochu cocktail. You may not like it, but you'll be a better person for it.
Pros: Good happy hour, excellent food (not just the sushi), great service
Cons: Limited parking options, but easy walk from the Pike Market
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