The key to successful of assessment reform depends on how teachers understand the concept and practices of assessment. Brown s (2003 & 2004) studies provided initiation for educators in this area. Different versions of Brown s questionnaire on teachers conceptions of assessment (TCoA-III) used both in Hong Kong and China rendered new insights and information into the wide range of conceptions and practices of assessment among Chinese practitioners (Brown, et al., 2006 and Li & Hui, 2007). These results showed that there might be fundamental difference in conceptions and practices of assessment between practitioners in a Chinese context and those in the West. Using interviews to tap into the minds of the local teachers, this study sets off to investigate the missing conception of assessment among Hong Kong teachers. Qualitative interviews were conducted among local practitioners of different backgrounds and subject specialists. The study is able to validate traditional, unwritten as well as unique conceptions of assessment held within Chinese teachers. Preliminary results show that there are cultural-specific as well as context-based differences. The former is illustrated by examples such as assessment as a way of promoting industriousness among students and assessment as differentiating brilliance in studying. The latter is supported by examples of using assessment to predict and boost the results of Territory-wide System Assessment which indicates individual school s standards in key learning areas for the purposes of school improvement. The results are helpful in revealing the possible cultural factors and their influences that contributes to the dissimilarities found in the conceptions and practices in assessment. It also provides insights of why these conceptions govern the ways in which assessment is practised in local schools. This missing link broadens our understanding about and allows us to better measure teachers conceptions and practices of assessment.