World Dirt Association (WDA) is an artist group made up of Yoshitaka Nanjo, James Jack and Shotaro Yoshino. Working together with diverse participants, they sample dirt from various places across the world and focus on the characteristics of each site based on the following nine principles:

  1. Explore and record the history of dirt
  2. Connect various researchers on the topic of dirt
  3. Collect dirt samples and analyze each one
  4. Focus on dirt from multiple viewpoints
  5. Make places for discussion associated with dirt
  6. Plan symposia, events and workshops
  7. Create artworks that utilize dirt
  8. Publishing research on dirt periodically
  9. Continuing activities related to these principles