Abstract: In this study,we investigate the evolution of Sino-U.S. competition in the chip equipment industry,focusing on the dynamic interplay of technological nationalism policies. We aim to understand how the United States’ restrictive measures and China’s support strategies interact over time and impact technological development in this strategically critical sector. We observe that the world has entered an era characterized by technological geopolitical uncertainty,where a “tech cold war” is reshaping global competition. The United States employs technological nationalism to restrict China’s access to key technologies,leveraging tools such as the “entity list.” Meanwhile,China counters with policies like the National Integrated Circuit Industry Investment Fund (the “Big Fund”) to strengthen its domestic capabilities. Our study critiques existing research that treats U.S. restrictions as static,one-time events. Instead,we adopt a dynamic perspective,analyzing the evolution of these policies and their long-term implications for both nations. Using the semiconductor industry as a case study,we examine this interplay at the level of specific technological fields. To achieve our goals,we use a knowledge graph approach. We decompose global semiconductor manufacturing patents into 88 technological fields,mapped based on their co-occurrence relationships. This allows us to explore how U.S. restrictions and Chinese support policies target specific technologies. By comparing the patent knowledge networks of U.S. entity list firms and Chinese firms supported by the Big Fund,we identify patterns of co-evolution. This analysis provides insights into the overlap and divergence between the two countries’ strategies. We find that U.S. and Chinese policies are not static but evolve over time. The United States has adopted increasingly specific restrictions,particularly during 2018—2020. However,these measures showed reduced continuity post-2020,influenced by shifts in political leadership. In contrast,China’s support policies through the Big Fund are remarkably consistent,focusing on building self-reliance in semiconductor design,manufacturing,and packaging. We also observe that the “needle-for-needle” adversarial strategy between the two countries peaked in 2020 and subsequently declined,suggesting adjustments in both nations’ approaches. Our findings reveal that both countries prioritize policies targeting high-centrality technologies:Primarily targeting fields with high technological importance,particularly those critical to national security. Emphasize commercially promising technologies rather than exclusively addressing “choke-point” areas. Despite rhetoric about tackling weaknesses,we find that China invests more heavily in areas where it already has competitive strength. Our analysis highlights that technological,market,and political factors shape policy decisions differently:Policies from both nations strongly focus on high-centrality fields in the knowledge network. Competitive fields attract more intervention from both countries. However,U.S. policies exhibit a greater focus on restricting scientific innovation,while China emphasizes supporting areas with immediate market potential. While U.S. measures show discontinuities influenced by political cycles,China maintains a steady trajectory of support,reflecting its centralized approach to industrial policy. We find that U.S. and Chinese strategies exhibit a moderate degree of co-evolution. While both countries target similar technological areas,their approaches reflect different priorities. The United States emphasizes maintaining its dominance in critical areas,while China seeks to reduce its dependence on foreign technologies. Our results suggest that while the term “decoupling” implies complete separation,the reality is more nuanced. Both nations exhibit overlapping interests,leading to a complex dynamic rather than outright divergence. We propose several avenues for future investigation:①Policy Drivers: Understanding the factors that influence countries’ choices of target technologies. ②Firm-Level Responses: Examining how firms navigate conflicting pressures from domestic support and foreign restrictions. ③ Micro-foundations of Decoupling: Analyzing how firm strategies and technological developments contribute to broader patterns of decoupling. In conclusion,we have shown that Sino-U.S. technological competition is a dynamic and evolving process. We provide evidence of co-evolution in their policies,with both nations targeting high-centrality and competitive fields. While the United States demonstrates fluctuations in its restrictions,China maintains a consistent trajectory of support. This interplay shapes the global semiconductor industry and has far-reaching implications for technological development. Our findings highlight the importance of understanding these dynamics at the level of technological fields rather than industries. By doing so,we reveal the subtleties in how policies are formulated and their impacts on innovation. We believe this approach can provide valuable insights for policymakers and researchers alike. We invite future studies to build on our methodology and findings to deepen the understanding of technological nationalism and its role in shaping global technological landscapes.