7 Japan

Story lines: Two-time 138.5-pound champ Kaori Icho (right) and mates could sweep all four women's wrestling weight classes; judo teams hoard medals, as always; Kosuke Kitajima, 29, tries to sweep men's breaststrokes for third straight Games.

Don't miss: Kohei Uchimura, the most dominant male gymnast of his era, who should win Japan's first all-around title since 1984.

Still going strong: At 71, equestrian rider Hiroshi Hoketsu, who first competed in the Olympics 48 years ago in Tokyo and is the third-oldest Olympian ever.

Outlook: With Tokyo bidding for the 2020 Summer Games, a strong showing could boost enthusiasm for the bid at home and within the IOC.