The figure of speech being used in the statement is a pun on the word "chord." In music, a chord refers to a harmonious combination of notes played together. By using this word, the sentence implies that the pianists were always in harmony with each other, both in their marriage and their musical performances. The deeper meaning behind the figure of speech suggests that the couple had a strong and mutually beneficial relationship.

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The statement uses a pun on the word "chord" to suggest that the pianists were always in harmony with each other, both in marriage and music.