On July 17, 1997, Oh summitted Gasherbrum II without supplementary oxygen, completing her first climb to a summit of over 8,000 meters. Over the next several years, she attempted several eight-thousanders without success. In 2004, she climbed Mount Everest with the aid of supplementary oxygen. In 2006, she added scaling Shishapangma to her list of accomplishments. At the time, two women, Edurne Pasabán and Gerlinde Kaltenbrunner, had completed nine different eight-thousanders to Oh's three. In 2007, she conquered Cho Oyu and K2, bringing her total 8000ers to five. Two other women achieved their 10th such climb that year. In 2008, Oh added four more 8000+ meter climbs, while the leaders in the chase for all 14 added only one each.