Katsu is a bit odd. To start, Katsu isn't its name. Aiya is. Unless you go by the business card. Or the large "Katsu" emblazoned on the staff's t-shirts. Or a rough and probably incorrect extrapolation from the owner's name -- one Mr. Katsuyama. His personality drives the place, a unique little izakaya among a Yan'an Xi Lu strip of them, with a menu stacked with quirky discoveries like deep-fried cheese and whale sashimi. He doesn't have Sprite, but the fridge is stocked with A&W Cream Soda and Diet Root Beer. Who carries chilled Diet Root Beer? There's a Chinese name --