Seven years ago, I bit into a delicate variety of seaweed called umi-budō, or "sea grapes." I remember sampling a few dishes at Unjami, an Okinawan-style izakaya off Nakano Broadway in Tokyo (5-55-1 Nakano, Nakano-ku, Tokyo; 03-5345-5836), but the umi-budō stood out as something special. These tiny, grape-like beads are eaten fresh with vinegar sauce, and are unforgettable once you've had them.

So, on a recent business trip to Okinawa, I made it my goal to savor this delicacy on its island of origin. Ryukyu Dining Yamoriya in Nago (5-14-24 Agarie, Nago-shi, Okinawa; 0980-52-3008) did not disappoint. Superbly crisp, the little translucent green beads tasted as fresh as I'd hoped. The refined taste and delicate popping sensation confirmed my love for this treat.

Umi-budō have a shelf-life of only around a week, which is perhaps one reason you won't find them in regular Tokyo supermarkets. At the airport in Naha they are available in souvenir boxes for around ¥500 to ¥1,000 (labeled as "green caviar," though I much prefer the plant-friendly term "sea grapes"). I've since learned that you can buy them at Washita Shop in Ginza (1-3-9 Ginza, Chuo-ku, Tokyo; 03-3535-6991; www.washita.co.jp/info/shop/ginza), and they are indeed staples at other Okinawan izakaya around the capital, such as Ryukyu Sakaba Gachimaya in Ebisu (1-13-3, Ebisu-Nishi, Shibuya-ku, Tokyo; 03-6415-3708).