V4641 Sgr campaign We schedule the optical spectroscopic observations of V4641 Sgr at Okayama, Japan from April 26 to 30. Our run will start on 14:30 (UT) and end on 19:30 (UT) for every 5 day. Simultaneous photomery is scheduled at Osaka kyoiku University. The giant outburst of this X-ray transient was observed on 1999 September 15. Its very fast activity is quite different from typical X-ray transients. This source is now at quiescence (13.8 mag). Simultaneous time-series photometry and other wavelength obsevations are encouraged. Anyone obtaining data will be invited to our collaboration. If the observations at other site are planning, please notice the schedule to uemura@kusastro.kyoto-u.ac.jp, or through vsnet-alert. Regards, Makoto Uemura, Taichi Kato, and Masami Honkawa