A lunch expedition to scout out noodles for next week’s Thin Wheat Line box just led me into the realm of the unexpected. I stopped in at the relatively new Tu Oanh (1207 S. Jackson) — “relatively new” means the “Grand Opening” sign on the window has only been there for six months. The menu listed all the normal noodles (pho, bun bo hue, hu thieu) representing each of the major culinary regions of the country (north, central, south), so it was hard to figure out what to try. So I turned to a handwritten wall special labeled “bun mang vit.” “What’s bun mang vit?” I asked the waitress.”It’s good. Vietnamese style food,” she replied. When pressed, she specified that it had duck. So I shrugged OK.She came back with three plates: The first was a bowl of clear brothwith broken rice noodles, some baby bamboo shoots, and cubes ofblood. Then there was a tiny bowl of what looked like nuoc cham, orfish sauce. And the third was a giant cabbage salad with herbs, friedshallots, and a steamed or poached duck breast, with bones. (I didn’tbring my camera, but you can see a decent picture here under “Duck Rice Noodle Soup,” and here are all the Flickr photos tagged “bun mang vit.”) I poured the sauce over the salad and meat; it turned out to be thick with grated ginger. The duck was still warm,and incredibly tender, when I chewed the meat off the bones. But apartfrom the caramelly fried shallots and the fat funk of the fresh bambooshoots — with all affection, I’d have to characterize the smell as mildly feculant — the soup had no flavor. I tried adding Sriracha, then salt fromthe shaker. Nothing. Another dose of salt. Then even more. Finally, the waitress came running over. “Is everything all right?” she asked. “Needs salt,” I said. “A lot more salt.” “That’s not salt. That’s sugar,” she replied. “You need to add the sauce.”So I dumped the rest of my bowl in, and suddenly, the soup transformed from water to a sweet-tart, gingery-spicy broth. The cubes of blood (I’m no blood conoisseur, but it was probably duck or pork blood) were incredibly creamy, with only a mild, metallic aftertaste. I scarfed down as much as I could take, but it was really a meal for two (for $8, no less).I don’t know if I’d recommend Tu Oanh’s bun mang vit to anyone who doesn’t already like blood cubes, fresh bamboo shoots, and bone-in duck, but it wasn’t bad. In fact, it’d be worth a Thin Wheat Line. Except the noodles were mush.