The appearance of a supernova in the Large Magellanic Cloud in February 1987 inspired various new activities in astrophysical research. The discovery of the supernova neutrino burst by the KAMIOKANDE and the IMB groups began new area of neutrino astronomy. The neutrino burst from SN1987A suggested the formation of a neutron star deep inside the dense exploding ejecta. Various phoenomena were suggested to check the acitivity of this pulsar, a magnetized rapid rotating neutron star.

On the other hand, supernovae and pulsars have been susupected to be the source of cosmic rays., In fact, their particle-acceleration activity has been checked observationally through synchrotron radiation from pulsars and SN remnants, and through possible high energy gamma ray emission by binary X-ray systems such as Cygnus X-3. Also, newly born pulsars and the very early stages of SN explosions are considered theoretically also to be plausible sources of high energy particles.

The early stage of the supernova explosion provides us with a unique chance to check the high-energy activity of a supernova and its pulsar, because the accelerated particles collide with the dense ejecta to generate high-energy gamma rays and neutrinos. These gamma rays and neutrinos may be detactable. This possibility was suggested in 1978 by a few authors, including myself.

When we heard about SN1987A, some Japanese physicists working on cosmic rays and high energy experiments immediately started a plan to search for extensive air showers produced by the high energy gamma rays using two methods of detection: a scintillator array and a Cherenkov light telescope. They contacted researchers in New Zealand and Australia to execute the observation in the southern hemisphere. Thus an international collaboration called JANZOS was formed in the Spring of 1987. As for the observation site, we chose Black Birch in the South Island of New Zealand. Overcoming various obstacles, the project proceeded very quickly and successfully and we started observations in October 1987 with the scintillator array and in November 1987 with the Cherenkov telescope.

As described in the following articles in this volume, our observations have been executed successfully. We have not yet gained clear evidence of high energy gamma rays from SN1987A, except for the January 1988 event associated with the X-ray flare observed by the GINGA satellite. This event, which is at our limit of detectability may be interpreted as Fermi acceleration accompanying the collision of the SN shock wave with the surrounding matter ejected from the SN progenitor. Our project will continue for a while, extending the search to other candidates sources of high energy gamma rays such as Cen A, Vela X-1 and others.

This project was made possible by much generous support. The members of the JANZOS are grateful to Professors J. Arafune and H. Sugawara for their support. We acknoledge Dr. D. Robinson for his hospitality at the Black Birch site. We appreciate the cooperation of the New Zealand Ministry of Works and Development (Blenheim Branch). This work is supported in part by a Grant-in-aide for scientific research from the Ministry of Education, Science and Culture, Japan, Yamada Foundation, Inamori Foundation, the University of Auckland Research Committee ,the University of Auckland Finance Committee, the New Zealand Scientific Research Distribution Committee, and the New Zealand University Grants Committee. We thank W.H. Allen of Carter Observatory.

H. Sato