Britain's Olympic archers have enjoyed mixed fortunes in the first round of the women's 70m individual event.
Alison Williamson, in her fourth Olympic games, defeated 50-year-old American Janet Dykman 147-121.
However, fellow Briton Helen Palmer found the going tough against Chinese ace Ying He, losing 141-130.
Meanwhile, Bhutan's Tshering Chhoden created a huge upset when she beat Chinese 11th seed Lin Sang by three points to reach the next round.
The 24-year-old scored 159 points to beat Lin by three points.
"The win is important for my whole country," said Chhoden, who along with fellow archer Tashi Peljor makes up the team from Bhutan.
Second seed Lee Sung-jin of South Korea thrashed Lamia Bahnasawy of Egypt by 43 points.
Her Korean team-mate and Sydney gold medallist, Yun Mi-jin, defeated Hanna Karasiova of Belarus 162-155.
"She was a little bit nervous when she fired her first arrows but by
the end of the end of the match she was very cool," said South Korea coach Baek Woong-ki.
"She will get better."
Philippines wildcard Jasmin Figueroa caused anotrher upset when she beat former world number one Natalia Valeeva of Italy by two points.