Mini-robots competing in the marathon
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Loneliness of long-distance robot

Five knee-high mini-robots have set off on the world's first robot marathon, the Robo Mara Full race in Osaka, Japan.

The battery-charged machines will race 423 laps around an indoor 100-metre track in Osaka's Asia Pacific Trade Centre.

The marathon is expected to continue until Sunday.

Roland Buerk reports.