BC UMa: superoutburst! growth of genuine superhumps! Dear Colleagues, We have received new sets of data from David Boyd and Kazuhiro Nakajima-san. Boyd's observation covered the important part of the early stage, which showed a slightly decayed early modulations (early superhumps?). Nakajima-san's 8-hr long observation last night clearly shows the growth of genuine superhumps (ampliude growing to 0.1 mag). The period of the signal is slightly longer than 0.064 d, which qualifies the signal as the genuine superhumps! However, the profile of these humps is slightly unlike those of usual SU UMa-type superhumps, particularly in that the rise is slower and there is some tendency of a double wave. It is possible, as in the transition of WZ Sge from early superhumps to genuine superhumps, the major peak of the early double-wave modulations eventually developed into genuine superhumps. BC UMa would become a key object in clarifying the peculiar behavior of WZ Sge-type dwarf novae! We have also received additional notes of successful observations during the past two days. We hope we will be able to fully illustrate the growth of superhumps in the very important system BC UMa. Further observations are very strongly encouraged. Please also send your observations to Uemura-san (uemura@kusastro.kyoto-u.ac.jp) and Ishioka-san (ishioka@kusastro.kyoto-u.ac.jp) in order to avoid a delay in communication. Regards, Taichi Kato VSNET Collaboration team