Items Authored by Douglas Silfen
- Great Whale Shogi. Great Whale Shogi by R. Wayne Schmittberger. (11x11, Cells: 121) Author: Douglas Silfen. Inventor: R. Wayne Schmittberger.
- Dai Dai Shogi. Extremely large Shogi variant invented in the 17th century. Author: Douglas Silfen and Eduard Werner.
- Great Whale Shogi. Large board based on Whale and Wa Shogi. Author: Douglas Silfen. Inventor: R. Wayne Schmittberger.
- Iron Guard Chess. Instead of a queen, white has an Iron Guard who can move only to adjacent diagonal squares and cannot be captured. Author: Douglas Silfen.
- Missile Chess. Missing description Author: Douglas Silfen. Inventor: R. Wayne Schmittberger.
- Trophy Hunt Chess. Capture at least one of each trophy animal to win. Author: Douglas Silfen and Karl Scherer.
- Wa Shogi. Large Shogi variant from the 17th century or earlier. Author: Douglas Silfen.
- Whale Shogi. Small Shogi variant. Author: Douglas Silfen and Karl Scherer. Inventor: R. Wayne Schmittberger.