Yamaoka started for the first time in the Snowboard World Cup in March 2002 in Sapporo . There she took sixth place. In the same month she became a Japanese Master. At the beginning of the 2002/03 season she won her first World Cup in Laax . In the further course of the season she reached five top ten placements in the World Cup and at the end of the season she was second in the Halfpipe World Cup. At the Snowboard World Championships in 2003 on Kreischberg , she was ninth. In the following season, she finished third twice and second once in the World Cup. She also won two World Cups and won the Halfpipe World Cup. After third place in the World Cup at the beginning of the 2004/05 season in Saas-Fee , she came in 24th place at the 2005 Snowboard World Championships in Whistler and 14th place at the 2005 Winter X Games in Aspen . In March 2005 she won her fourth World Cup in Lake Placid and finished third in the Halfpipe World Cup at the end of the season. In the 2005/06 season she won the World Cup in Whistler and came in second place in Furano . In January 2006 she won the bronze medal at the Winter X Games 2006 . At the highlight of the season, the 2006 Winter Olympics in Turin , she was tenth. She finished the season in ninth place in the Halfpipe World Cup. In the following season, she came under the ten four times in the World Cup, including twice in second place and at the end of the season reached fourth place in the Halfpipe World Cup. She also finished third at the Burton New Zealand Open in Snow Park and second at the World Superpipe Championships in Park City . At the Snowboard World Championships 2007 in Arosa she won the silver medal. After finishing fifth in January 2008 at the Winter X Games 2008 in Aspen , she took two second places in the World Cup. In February 2008, she became a Japanese Master. The following month, she finished fourth at the Burton US Open and third at the World Superpipe Championships in Park City . She finished the 2007/08 World Cup season in seventh place in the Halfpipe World Cup. In the 2008/09 season she won third place at the World Cup in Gujo and her sixth and last World Cup victory in Stoneham . At the 2009 World Snowboard Championships in Gangwon , she was fourth. At the end of the season, she came third in the Halfpipe World Cup. At the beginning of the 2009/10 season she took third place at the US Snowboarding Grand Prix in Copper Mountain . In January 2010, she finished fourth at the Winter X Games 2010 . At the season highlight, the 2010 Winter Olympics in Vancouver , she achieved 16th place. At the beginning of the 2010/11 season she finished third at the Burton New Zealand Open in Cardrona . In the further course of the season she completed her last World Cup in Saas-Fee and came in fourth. At the Winter X Games 2011 in Aspen , she came fourth. In February 2011 she was third on the Winter Dew Tour in Ogden . The following month she reached eighth place at the Winter X Games Europe 2011 in Tignes and fourth place at the Burton US Open. At the 2012 Snowboard World Championships in Oslo , she was eighth. After the 2011/12 season, she ended her career.
Japan
World cup
TTR World Snowboard Tour
Laax
Stoneham
Kreischberg
Lake Placid