It is of great theoretical and practical significance to explore technological breakthroughs especially in fostering innovation and advancing technological progress. Existing technological breakthrough research focuses on the novelty and impact assessment of technologies, while generally ignoring the potential breakthrough progress that can arise from the upgrading of technologies that are not novel. Technological improvements toward non-novel technical issues will largely involve longstanding technical challenges and are therefore a daunting task. Overcoming these challenges is, in essence, a process of technological breakthrough, as is the creation of something new. This study first advocates that technological inventions aiming to overcome longstanding technical challenges should be recognized as technological breakthroughs if they have generated widespread attention within the domain and spurred a series of technical endeavors. This expands the conventional understanding of technological breakthrough, which focused on “novelty” or “impact”, or a comprehensive consideration of both. In addition, we propose an operational methodology and process for identifying these breakthrough inventions, which can further enable us to recognize technology opportunities and proactively manage technological innovation. 1. Identifying the invention targeting non-novelty technical issues. This study argues that if a technological innovation activity references a set of prior technical patents concentrated in an earlier period, then this technological innovation activity is likely to address a longstanding, persistent technical issue (non-novelty technical issue). 2. Measuring the breakthrough nature of invention. This study examines three aspects: technological difficulty, technological impact, and technological communicability. 1) The higher the technological difficulty, the greater the breakthrough significance of the patent technology activity. 2) The greater the impact of the technology, the more substantial the technological progress achieved by the patent technology activity. 3) The better the communicability of the technology, the more substantial the contribution and inspiration of the patent technology to the development of the field. 3. Analysing and validating breakthrough inventions. For verifying the identified breakthrough invention results, firstly, a comprehensive comparison of the results of relevant studies was conducted. Second, the opinions and assessments of experts in the field were sought. Their expertise can provide valuable insights and validation to further ensure the reliability of the present methodology.