Sarah H. Swords Schaffner, 89, a former missionary in Japan who was a member of church, political and international organizations here, died of congestive heart failure Tuesday at her home in Washington.

Mrs. Schaffner was born in Lancaster, Pa., and was a teacher there until her marriage in 1915 to the Rev. Paul Franklin Schaffner, a minister of what was then the Reformed Church and now is the United Church of Christ. They spent the next 10 years as missionaries in Japan.

After Mr. Schaffner's death in 1925, Mrs. Armstrong returned to Lancaster, where she later worked for the Armstrong Cork Co. In 1942, she was named dean of residents at Catawba College in Salisbury, N.C. In 1944, she moved to Philadelphia, where she was a teacher.

From 1947 to 1955, Mrs. Schaffner lived and traveled in India, Czechoslovakia, Sicily and Canada with a daughter, Louise Schaffner Armstrong, a Foreign Service officer.

Since 1955, she had lived in Washington and here she was a member of the Washington Committee for Japan International University, the English-speaking Union, Ikebana International, the Women's National Democratic Club and the Washington Club. Throughout her life, Mrs. Schaffner had sung in church choirs and in concert and she was a member of the choir of St. Patrick's Episcopal Church in Washington. She also was a member of the vestry.

In addition to Mrs. Armstrong, of Washington, survivors include two other children, Franklin J., of Santa Monica, Calif., and Dr. Isabelle R., of Washington, and three grandchildren.