The researchers developed a new classification system for Japanese forest vegetation using traditional methods and a large dataset. They identified 34 alliances, 14 orders, and six classes within the Japanese forests. The classification system was effective in grouping vegetation based on characteristic species and environmental factors. The lower-level units were more specific in their environmental requirements, while the higher-level units encompassed a broader range. This classification system provides a solid foundation for future revisions of phytosociological systems in East Asia.