North Korea has issued new stamps to mark the 65th anniversary of the signing of its mutual defense treaty with China and Chinese President Xi Jinping's state visit to Pyongyang last month. The Pyongyang-based Korea Stamp Corp. unveiled the two stamps on its website — one commemorating the signing of the North Korea-China Treaty of Friendship, Cooperation and Mutual Assistance on July 11, 1961, by the North's state founder Kim Il-sung and then Chinese Premier Zhou Enlai, and the other marking Xi's June 8-9 state visit to North Korea, his first in seven years. The corporation described the summit between the two leaders as "a historic occasion that opens a new era of friendship and cooperation, carrying on the tradition through generations and blazing a trail toward a more beautiful future." At the summit, North Korean leader Kim Jong-un and Xi vowed to strengthen bilateral ties through expanded exchanges across multiple sectors, from economy to culture, as well as more frequent high-level visits. The two leaders have since exchanged letters on the occasion of Xi's birthday on June 15 a