This study aims to develop a conceptual framework regarding practitioner knowledge and describe how one mathematics teacher generates her practitioner knowledge based on the framework. The characteristic of this framework is a combination of static and dynamic aspects of knowledge based on the teacher's perception and interpretation. The research subject was an experienced female teacher in Japan who specialised in mathematics teaching. Her lessons on multiplication tables were observed and a semi-structured interview was conducted regarding observable behaviours after the lesson. The analysis showed that the teacher changed the timing of introducing the generalisation of multiplicands and multipliers. Moreover, we observed that this change occurred after conversation between the interviewer and self-reflection. It was interpreted as a dynamic aspect of practitioner knowledge and called knowledge generation. This study analysed further the knowledge generation using the framework with reference to the practitioner's situation-specific knowledge. Here, situation-specific "knowledge" is modified from the situation-specific skills (Blömeke et al., 2015) because it is knowing and judging the situation using closely related to a judgement of action caused by perception of the situation. The analysis concluded that a new situation-specific knowledge was generated through the interaction with the situation utilising the static aspect of knowledge, stimulated by external objective view. In other words, the teacher recast current situation-specific knowledge and static aspect of knowledge, and developed a new situation-specific knowledge that augments static aspect of knowledge as well.