context: In November 1873, when Gojong proclaimed his parents, Heungseondaewon, who had been in power for ten years, was dismissed, and the Yeungheung Min regime, led by the empress of fame, was established. As a result, the naturalization of trademen, the foreign policy of Joseon began to change little by little. In this situation, Japan, which abandoned peaceful negotiations with Joseon, entered the Ganghwa Island illegally by the Japanese warship Unyoho to enter into a trade treaty on September 20, 1875. Battle with Unyoho caused the incident. Japan forced Joseon to open port against this force. In Korea, the pros and cons were mixed, but in the end, the position of the proponents of the port was strengthened, opening the doors by signing the Ganghwado Treaty with Japan on February 3, 1876. As a result, Joseon, which had been using the policy of closure, opened ports in Busan, Incheon, and Wonsan. Since the conclusion of this treaty, Japanese forces gradually penetrated into the country, threatening and tricking, and in 1910, plundering Korea's sovereignty. Gojong was impressed by reading the book, “The Korean Strategy,” which was brought to Japan by the receiver Kim Hong-jib, who sent him to Japan. Subsequently, he sent a shrine excursion to Japan and a missionary to the Qing Dynasty.
question: When did the closure policy of Korea collapse?
answers.text: February 3, 1876