On September 21, during a ceremony at NAOJ mitaka campus in Japan, a memorandum of understanding for the East Asian Core Observatories Association (EACOA) was signed by the Head vice Director of National Astronomical Observatories of Chinese Academy of Sciences (NAOC), Dr. Zhao Gang, the President of Korea Astronomy and Space Science Institute (KASI), Dr. Seok Jae Park, the Director of Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), Dr. Paul Ho, and the Director General of the National Astronomical Observatory of Japan (NAOJ), Dr. Norio Kaifu in the presence of lots of guests from the East Asian countries.