Millennium 3D chess is a threedimensional chess variant created by William L. d'Agostino in 2001. It employs three vertically stacked 8×8 boards, with each player controlling a standard set of chess pieces.^{[1]}^{[2]} The inventor describes his objective as "extending the traditional chess game into a multilevel environment without distorting the basic game."^{[3]}
Millennium 3D сhess extends the traditional (twodimensional) game of chess into a multilevel environment.
For notation purposes, the three board levels are denoted 1, 2 (the middle board), and 3. Moves are recorded in the same manner as chess, using algebraic notation, with the only difference that each square is prefaced by its level number. The white and black armies begin, in standard formation, on boards 1 and 3 respectively.
All pieces can always move as normal while staying on the same board. Additionally, every piece is able to move between boards. Each piece's additional permitted movement in the third dimension is extended from its conventional 2D movement as follows:
 
Initial setup

 
Movement of the rook and knight

 
Movement of the bishop and queen

 
Movement of the pawn and king. Squares marked × are capturing moves for the pawns.

George Davis vs. William d'Agostino, corr. 2006:
1. ♘2g3 ♝2b7 2. ♗3e3 ♞3c6 3. ♘2b3 ♝2g7 4. ♘2a5 ♛1b6 5. ♘3c5 ♛×1b2 6. ♘×3b7 ♛3b4 7. ♘3c5 ♛3e1+ 8. ♕2e1 ♛3c3+ 9. ♔2f1 ♛×1a1 10. ♕2c1 ♝2a6+ 11. 2e2 ♛×1a2 12. ♘2c7 ♜2h7 13. ♘1e7+ ♚2e8 14. ♘1c6 ♜1c8 15. ♘×3c7 ♜×1c2 16. ♕2c7 ♛2b1+ 17. ♔1g1 ♞3e5 18. ♕1d7+ ♚2f8 19. ♗2f4 ♛2d1 20. ♗×3e5 ♛3e1+ 21. ♔2g1 ♛×3e5 22. ♕2e7+ ♚1g7 23. ♕×3d7 ♝2d4+ 24. 2e3 ♜2c1+ 25. ♔1g1 ♛3g3+ 26. 2g2 ♜2f1+ 27. ♘×2f1 ♝3e3+ 28. 2f2 ♛×2f2# 0–1