The first thing we noticed about this clean, sleek eatery was that there were no rainbows. Rather, it was a cleverly designed multi-level space in shades of black, white and avocado, divided into a zashiki (Japanese-style room) and cozy alcoves, and dominated by a boardroom-long marble-topped communal table. In fact, if not for the two men in chef whites rolling rice and delectable edibles, we could have been in a high-tech European design center.

Having been politely turned away on Friday night for lack of a reservation, we waltzed in at noon on Saturday, and scored a semi-private table with a leafy view of Azabujuban-odori. We celebrated with a white wine Mojito (¥900), bursting with lime and mint, and a strawberry smoothie (¥800), which made us homesick for strolls down the Santa Monica Promenade. Comfy and ready to chow down, we kicked off with two tantalizing appetizers: stuffed avocado, with maitake (dancing mushroom), white fish and anchovy sauce (¥1,200); and tuna and shrimp sashimi spring rolls, wrapped inside with fresh spinach leaves, outside with crispy yuba (concentrated tofu), and decorated with a basil and peppercorn sauce (¥1,100). Divine, with a rich fusion of flavors, they vanished quickly. 

Choosing our “main” rolls from the Japanese/English menu proved to be a challenge, so we followed our trilingual Russian waiter's advice. First up, the “traditional” Rainbow Roll (¥1,400), six giant pinwheels so chock full of salmon, squid, shrimp and tobiko (flying fish roe) that everything tumbled out as we ate. Next, the “American” Spicy Negihamachi Roll (¥1,100), an innovative mix of shichimi (seven spice seasoning), yellowtail, leeks, and mayonnaise, in a roll of rice sprinkled with finely chopped green onions. It didn't seem American (size-wise), but it did make our eyes water—and we downed it in a snap. The afternoon crowd of 30-something locals and expats started flowing in, so we glanced at the “Original” rolls, closed our eyes and pointed: sautéed pork with an apple/sour cream sauce (¥1,000). Served in an oblong tray and garnished with red chili peppers, it certainly looked like sushi, but that's where the comparison ended. This seemed like something Mom might whip up during the holidays, except for the addition of a Chinese sweet miso paste, which made the sauce come alive in ways we hadn't imagined. 

We couldn't recall desserts being offered on any sushi bar menu, but Rainbow had a short, sweet list, and we couldn't resist. The delicate and dreamy matcha mascarpone mousse (¥700), and the chocolate bread pudding (¥700), topped with whipped cream and mint leaves, oddly seemed like the perfect ending. While not big on volume, Rainbow Roll Sushi does offer a contemporary take on a traditional dish, and since we like flavorful adventures, we weren't disappointed.