1. Title: Connect-4 opening database

2. Source Information
   (a) Original owners of database: John Tromp (tromp@cwi.nl)
   (b) Donor of database: John Tromp (tromp@cwi.nl)
   (c) Date received: February 4, 1995

3. Past Usage: not available

4. Relevant Information:
   This database contains all legal 8-ply positions in the game of
   connect-4 in which neither player has won yet, and in which the next
   move is not forced.

5. Number of Instances: 67557

6. Number of Attributes: 42, each corresponding to one connect-4 square

7. Attribute Information: (x=player x has taken, o=player o has taken, b=blank)

   The board is numbered like  6 . . . . . . .
                               5 . . . . . . .
                               4 . . . . . . .
                               3 . . . . . . .
                               2 . . . . . . .
                               1 . . . . . . .
                                 a b c d e f g

    1. a1: {x,o,b}
    2. a2: {x,o,b}
    3. a3: {x,o,b}
    4. a4: {x,o,b}
    5. a5: {x,o,b}
    6. a6: {x,o,b}
    7. b1: {x,o,b}
    8. b2: {x,o,b}
    9. b3: {x,o,b}
   10. b4: {x,o,b}
   11. b5: {x,o,b}
   12. b6: {x,o,b}
   13. c1: {x,o,b}
   14. c2: {x,o,b}
   15. c3: {x,o,b}
   16. c4: {x,o,b}
   17. c5: {x,o,b}
   18. c6: {x,o,b}
   19. d1: {x,o,b}
   20. d2: {x,o,b}
   21. d3: {x,o,b}
   22. d4: {x,o,b}
   23. d5: {x,o,b}
   24. d6: {x,o,b}
   25. e1: {x,o,b}
   26. e2: {x,o,b}
   27. e3: {x,o,b}
   28. e4: {x,o,b}
   29. e5: {x,o,b}
   30. e6: {x,o,b}
   31. f1: {x,o,b}
   32. f2: {x,o,b}
   33. f3: {x,o,b}
   34. f4: {x,o,b}
   35. f5: {x,o,b}
   36. f6: {x,o,b}
   37. g1: {x,o,b}
   38. g2: {x,o,b}
   39. g3: {x,o,b}
   40. g4: {x,o,b}
   41. g5: {x,o,b}
   42. g6: {x,o,b}
   43. Class: {win,loss,draw}

8. Missing Attribute Values: None

9. Class Distribution: 44473 win(65.83%), 16635 loss(24.62%), 6449 draw(9.55%)