宛名のない手紙: The Forest of Anonymous Letters

Field notes

Letters are released without names or recipients and reach an unspecified reader, who can respond only with a feeling stamp rather than a written reply. The app pairs that low-pressure exchange with a collecting loop: users choose papers, feed a fairy from a menu of named treats, pursue branching forms and secret rares, and retain discoveries in a catalog. The site also documents reporting and blocking controls and says an Android version is in development.