This state diagram traces the historical spread of Zen Buddhism from Indian Mahāyāna roots through early Chinese Chán, the Five Houses, and its transmission into Japanese Rinzai, Sōtō, Seon, and Thiền lineages, culminating in modern Western schools. Rendered with Mermaid.js, the diagram is loaded from an external `.mermaid` file via `fetch()` and drawn into the DOM using `mermaid.render()`. Nested state subgraphs organize regional details, while labeled edges indicate influences and diminishing lineages.