Philatelic Week Issued on April 20, 1990 (Heisei 2) In April 1990, the Ministry of Posts and Telecommunications issued stamp hobby weekly stamps and small sheets. This time, Ota Chou's painting "Woman Looking at the Stars"was adopted. Chou Ota was a Japanese painter who was active from the Taisho era to the Showa era, and painted traditional Japanese paintings using rock paints.