The developments of internally HIDiC since 1950's up to the present are presented. Since 1980's, researches on distillation columns with the SRV method were carried out under the name of the HIDiC in Japan. They further analyzed and modified the original arrangement of the SRV method. From 1990's, a national project on the HIDiC in Japan was conducted. In the project, the structure, the performance, the dynamic response, and the control strategy for the HIDiC were studied by both experiments and simulations. With an example of benzene-toluene separation, an energy saving of 30% in average was achieved by the prototype HIDiC. It was operated even without any condensers. Since then, the commercialization of the HIDiC becomes the next big target. From 2002, the next phase of national project on the HIDiC, with Maruzen Petrochemical, Kimura Chemical Plants, Kansai Chemical Engineering, Taiyo Nissan, Kobelco, and AIST (project leader) was started to industrialize the HIDiC as a key technology for the energy savings of chemical industries. In the project, there is a plan to separate the twelve-component hydrocarbons, which is one of the real mixtures in a chemical complex, by the pilot HIDiC. The reduction of CO2 emission by the HIDiC is estimated to be > 50% compared with the conventional column, resulting from the pilot plant experiment. This is an abstract of a paper presented at the 2006 AIChE National Meeting (San Francisco, CA 11/12-17/2006).