This gallerylike space in Downtown's out-of-the-way warehouse/artist loft district has been the secret of sushi connoisseurs since 1991. At the back of R23's single, large dining room, the 12-seat sushi bar shines like a beacon; what appear at first to be ceramic wall ornaments are really stylish sushi platters hanging in wait for large orders. More functional art reveals itself in the corrugated cardboard chairs -- they're funky, yet far more comfortable than wood! Genial sushi wizards stand in wait, cases of the finest fish before them. Salmon, yellowtail, shrimp, tuna, and scallops are among the always-fresh selections; an excellent and unusual offering is seared toro, where the rich belly tuna absorbs a faint and delectable smoky flavor from the grill. Though R23's sublimely perfect sushi is the star, the short but inventive menu also includes pungent red miso soup, creamy baked scallops, finely sliced beef "sashimi," and several other choices. Browse among a wide selection of premium wines and sakes (try the addictively sweet nigori).