  Since its first release in 2004, the CAS Journal Ranking, a ranking system of
journals based on a citation impact indicator, has been widely used both in
selecting journals when submitting manuscripts and conducting research
evaluation in China This paper introduces an upgraded version of the CAS
Journal Ranking released in 2020 and the corresponding improvements. We will
discuss the following improvements: (1) the CWTS paper-level classification
system, a fine-grained classification system, utilized for field normalization,
(2) the Field Normalized Citation Success Index (FNCSI), an indicator which is
robust against not only extremely highly cited publications, but also wrongly
assigned document types, and (3) document type difference. In addition, this
paper will present part of the ranking results and an interpretation of the
features of the FNCSI indicator.
