Robertson (1986) Subclassification on Sensitive Fine Grained Soils using CPTu is of interest since the variation of these soils include those of Consolidating Soils. However, the classification does not go into detail such as the influence of the existence of excess pore pressure prior to penetration testing or what is the contribution of the excess pore pressure to the total penetration resistance. Rahardjo et al (2008) studied this phenomena by extrapolation of the dissipation test data to determine the residual excess pore pressure which play an important role in CPTu testing. Further, Rahardjo et al (2016) continued investigation of the CPTu in Consolidating Soils using Bq, Bq* and Effective Stress Concept. These findings have been very useful when using CPTu in very soft soils and ultrasoft soils where the undrained shear strength of the soils is very low. This paper is the results of several studies of CPTu testing in marine clays, lacustrine, ultrasoft soils or even peats. The research including the application of data used for forensic investigation as well as revealing new fact on the advantages of CPTu to interpret the sliding plane. The author found that there is a jump on Bq value when sensing sliding plane. Bq and Bq* are parameters of importance when dealing with soft soils and discussed in more detail. Recent applications are in ultrasoft mud at North Jakarta, peats, and East Java mud eruption are also included.