Hiroko Kawata, a tour guide with the nonprofit organization Japan for Sustainability, covers her microphone with her hand and whisper-rehearses a section from her handwritten notes, running over a few words and the trickier English phrases. She nods to Julie Emmings, her British companion, who unfurls an orange bandanna attached to a branch, thrusts it in the air and waves a signal to get going. And we're off, into the wilds of the 11th Eco-Products Exhibition at Tokyo Big Sight in Koto Ward.

Considering the fact that there were a total of 721 companies and organizations represented at this year's show, we were thankful for the guidance provided by Japan for Sustainability. Over three days, the fair was visited by 182,510 people — around 8,500 more than last year. Companies ranged from Japanese giants such as Toyota, Panasonic, Mitsubishi, Mizuho, Meiji and Sapporo to one-person booths manned by entrepreneurs eager to showcase their wares.

Among the big corporates, Sanyo Electric Co, Ltd. showed off what $100 billion can buy in research and development: a giant solar-panel disc, capable of charging electric cars. But the company also focused on smaller projects such as the "eneloop" bicycle. Though it is yet to go into production, Sanyo already envisions the bicycle being a part of everyday life, where it can be docked and recharged at bicycle stands equipped with solar-paneled roofs. Thinking even smaller, the company also introduced solar-panel cell-phone rechargers, which give 20 to 40 minutes of talking time for every hour of charging.