International Letter Writing Week Issued on October 6, 1988 (Showa 63) In October 1988, the International Letter Writing Week stamp was issued. This is an international week that contributes to world peace through mutual understanding through correspondence. It is set every year for a week from October 9, the date of formation of the Universal Postal Union (UPU). The stamps are designed by Utagawa Kunimasa's painting "Iwai Kumesaburo's Chiyo" and Utagawa Toyokuni's painting "Third generation Ichikawa Komazo's Sasaki Ganryu".