  We use the CP trajectory diagram as a tool for pictorial representation of
the genuine CP and the matter effects to explore the possibility of an in situ
simultaneous measurement of \delta and the sign of \Delta m^2_{13}. We end up
with a low-energy conventional superbeam experiment with a megaton-class water
Cherenkov detector and baseline length of about 700 km. A picturesque
description of the combined ambiguity which may arise in simultaneous
determination of \theta_{13} and the above two quantities is given in terms of
CP trajectory diagram.
