The kkh plugin for Obsidian allows users to convert text between old and new styles of Japanese kana and kanji. It offers six types of transformations, including converting from modern to traditional kana, traditional to modern kana, modern to traditional kanji, and traditional to modern kanji. The plugin also supports conversions for combined styles like modern kana and kanji to traditional equivalents and vice versa. Users can select text in the editor and apply transformations through the ribbon menu, command palette, or text menu, with support for macOS, iOS, iPadOS, and Android. This plugin streamlines the process of switching between different versions of Japanese writing, making it a valuable tool for linguists, historians, and anyone working with older Japanese texts or modernizing traditional content.