The mayor of Osaka, Japan, is ending its "sister city" relationship with San Francisco this week, following a dispute over a statue that honors women and girls who were sexually enslaved by Japan's Imperial Army during World War II.The Column of Strength memorial consists of three women in bronze who are holding hands in a circle as they look into the distance. An older woman stands to the side. The statue commemorates "comfort women," a euphemism for thousands who were forced, coerced and deceived into serving men at brothels near the front lines.But the monument's inscriptions about the comfort women "present uncertain and one-sided claims as historical facts," Osaka Mayor Hirofumi Yoshimura contended in a 10-page letter dated Tuesday to Mayor London Breed of San Francisco. Yoshimura called the information an "interpretation" that has yet to be proved — adding that the number of women who were enslaved and how they were treated during their time in captivity were embellished.He also said the statue singled out Japan for atrocities and that raising awareness about sex trafficking "should consist of words equally applicable to all countries."According to the letter, Japanese authorities reached out seven times to San Francisco's previous mayor, Ed Lee, who died in 2017. The statue was installed last year."We're very saddened by his actions," Lillian Sing, a retired Superior Court judge who co-chairs the "Comfort Women" Justice Coalition, toldThe San Francisco Chronicle. "It provides no leadership and no vision for the future except for his continued denial of history."Experts say thousands of women were targeted. "The Japanese military was responsible for the setting up, use, operation and control of the comfort stations," an International Commission of Jurists report found. Investigators described life at the brothels as "living hell" for women: