In 1989, Yamamoto came ninth at the Osaka International Ladies Marathon.

[4][5] She was over 2 minutes, and over 0.5 miles (0.80 km) behind race winner Olga Markova.

[5] Her second place was the best result by a Japanese woman at the Boston Marathon,[6] and her time of 2:26:26 tied the Japanese national marathon record.

[7] Yamamoto was not selected for the 1992 Summer Olympics in Barcelona, Spain.

[8] Later in the year, Yamamoto came third at the 1992 New York City Marathon in a time of 2:29:58.