​In the west of the central Zagros prehistoric cultural sequence, the chalcolithic period started with the so-called J ware period. This name became familiar in the archaeology of western Iran from an archaeological survey of the Mahidasht area in 1975-78 directed by L. Levine. J ware is characterized by well fired slipped and painted ceramic influenced by Halaf ceramic culture from northern Mesopotamia. The J ware was reported from more than 60 archaeological sites in the Mahidasht region. However, what we know about this ceramic style is confined to a few white and black pictures of J ceramics, plus some general information about the ceramic published in 1975 by the Mahidasht expedition. Obviously such information to study such an important cultural period is not enough and more study is needed in this regard.  Therefore, many questions concerning the naming of J pottery, the chronology of this ceramic, pottery technique, slips, paintings, temper and more remain unanswered. Therefore, in order to answer this questions and give a clearer picture from the early Chalcolithic period pottery style, with the permit of the Director of the Mahidasht  Project and the Director of the National Museum of Iran, the J ware of the Mahidasht project, stored in the National Museum of Iran, was surveyed and analyzed completely after a few decades. The J ware of the Mahidasht project is documented by authors completely. In this study we took pictures, made line drawings, and described all the shreds in terms of temper, paintings, slip, paintings and more. The main goal of the present paper is to describe and explain the early Chalcolithic period culture of west central Zagros after such a long time since 1975. The result of this study is a clearer and more complete picture of J ware culture. The current study can be considered as the most complete source for the early Chalcolithic period of the Mahidasht region. Our preliminary analysis shows that the J ware is an eastern variant of the late Halaf culture in the central Zagros in western Iran.