 The painting was protected by glass because a few years earlier a man who claimed to be in love with the painting had cut it with a razor blade and tried to steal it.Since then, bulletproof glass has been used to shield the painting from any further attacks.Subsequently, on 21 April 1974, while the painting was on display at the Tokyo National Museum, a woman sprayed it with red paint as a protest against that museum's failure to provide access for disabled people.