Formal concept analysis is a data analysis method based on concept lattice, while decision implication and variable decision implication are two decision knowledge representations of formal concept analysis. Both decision implication and variable decision implication have complete inference rules for knowledge reasoning. In order to further clarify the differences between variable decision implication and decision implication, this paper first eliminates uncertainty from variable decision implication and introduces restricted variable decision impli-cation. Then, based on the related research on variable decision implication, this paper presents semantic and syntactic characteristics of restricted variable decision implication. On this basis, a complete set of inference rules is obtained for restricted variable decision implication, and decision implication and restricted variable decision implication are compared from the syntactic perspective. Besides, this paper further discusses the differences between the two decision types in knowledge representation and reasoning from the semantic perspective, and summarizes the characteristics of restricted variable decision implication relative to decision implication from the semantic and syntactic perspectives. These conclusions provide new ideas for comparative research of different decision types such as decision implication, variable decision implication, and fuzzy decision implication, as well as a new perspective for introducing more efficient and concise inference rules.