WZ Sge: rapidly brightening! Our preliminary photometry of WZ Sge shows a rapidly brightening of the object. We started time-series observation at 14:30 (UT) and the object was about 9.5mag at that time, and then, now (17:00 UT) we estimate the object is about 9.1mag, which indicates the rising rate is about 3.8 mag/day. As in the recent case of RZ Leo and AL Com, WZ Sge stars show "early superhump" during the very early phase of their outbursts. Tonight observations are important to study the birth of early superhumps. As well as follow-up photometric observations, tonight spectroscopy is strongly urged. As reported by Dr. Kuulkers, the object may show short-period oscillations during the rising phase, so observers should take CCD images with an exposure time as short as possible. The Kyoto team is now observing with an exposure time of 10s (25-cm SC + ST-7E). Regards, Makoto Uemura