Shape of the Unitary Triangle and Phase Conventions of the CKM Matrix

A shape of the unitary triangle versus a CP violating parameter \delta depends on the phase conventions of the CKM matrix, because the CP violating parameter \delta cannot directly be observed, so that it is not rephasing-invariant. In order to seek for a clue to the quark mass matrix structure and the origin of the CP violation, the dependence of the unitary triangle shape on the parameter \delta is systematically investigated.