Confronted with demographic contraction and accelerated digital transformation, Japan's publishing industry has undergone significant structural reconfiguration. The decline in print circulation, coupled with the shrinking domestic readership base, has compelled publishing enterprises to seek new growth trajectories beyond national borders. Within this context, the manga sector has emerged as a pivotal force sustaining industrial resilience and international cultural influence. However, the globalization of Japanese manga is not merely the result of market expansion; rather, it represents a systematic reconstruction of production, distribution, and cultural mediation mechanisms under conditions of structural constraint. Focusing on Shueisha, Kodansha, Shogakukan, and Kadokawa, this study analyzes the international communication strategies of Japan's four major manga publishing houses. By integrating theoretical discussions on cross-cultural circulation with empirical industrial analysis, this study examines how these four publishing houses have built a globally oriented dissemination system through coordinated strategies in intellectual property (IP) integration, digital platform construction, AI-assisted translation, overseas institutional deployment, capital collaboration, and talent cultivation. The findings indicate that Japanese manga publishing houses have established a multi-layered global communication model. Through the "Media Mix" framework, manga IPs are transformed into cross-media narrative ecosystems spanning animation, film, gaming, and merchandise, thereby enabling cultural content to function as expandable symbolic capital. Simultaneously, digital platforms and global simultaneous releases reduce temporal gaps between domestic and overseas markets, effectively responding to piracy and enhancing user engagement. AI-driven translation technologies further improve scalability and localization efficiency, while overseas subsidiaries and cross-sector alliances facilitate localized management and resource integration. In addition, global creator incubation platforms and bidirectional talent mobility mechanisms strengthen the sustainability of transnational content production. Nevertheless, the international success of Japanese manga is deeply embedded in its specific historical experiences, aesthetic traditions, and institutional configurations. Its cross-cultural appeal results from dynamic coordination between cultural distinctiveness and global adaptability, achieved through continuous strategic adjustment in production, distribution, and organizational systems over time. As such, Japan's trajectory provides an important comparative case for understanding how cultural industries respond to structural domestic constraints while proactively engaging and reshaping global markets. For China's manga publishing industry, the strategic objective is not replication but structural upgrading and long-term capacity building within an increasingly competitive global environment. Future development should aim to establish a coordinated system that integrates policy support, technological innovation, IP value chain extension, digital platform construction, talent cultivation, and copyright governance in a mutually reinforcing manner. By enhancing global distribution efficiency, strengthening international cooperation mechanisms, expanding diversified cultural exchange channels, and promoting sustainable content production, China's manga industry can gradually develop a competitive and resilient international communication framework, thus contributing to more diversified, balanced, and sustainable global cultural exchange in the digital era.