CWJess: Implementation of an expert system shell for Computing with Words. Computing with Words (CW) is an emerging paradigm in knowledge representation and information processing. It provides a mathematical model to represent the meaning of imprecise words and phrases in natural language, and to perform reasoning on perceptual knowledge. This paper describes a preliminary extension to Jess, CWJess, which allows reasoning in the framework of Computing with Words (CW). The resulting inference shell significantly enhances the expressiveness and reasoning power of fuzzy expert systems and provides a Java API which allows users to express various types of fuzzy concepts, including: fuzzy graphs, fuzzy relations, fuzzy arithmetic expression, and fuzzy quantified propositions. CWJess is fully integrated with jess and utilizes jess Rete network to perform a chain of reasoning on fuzzy propositions.