Logic Masters Deutschland e.V.

F'red' and Schwartz decide to play a game. They chose to play Connect four, but on a sudoku board. F'red' goes first and plays red, and naturally Schwartz plays black.

To play Connect Four, normally players take turns dropping pieces from the top of the board, as far down as they can go, and the game ends when someone get's Four-In-A-Row either horizontally, vertically, or diagonally.

In this version, every play is numbered, 1 to 9, and then loops around again. So Red's first seven plays are 1, 3, 5, 7, 9, 2, 4, and black's first five plays are 2, 4, 6, 8, 1, 3, 5... and so on. For most of the game, sensible moves are possible, but frequently, normal sudoku rules prevent players from being able to play in certain locations.

After many turns, Shwartz shouts "Connect-Four! I win!"

Fred asks, "Shucks. Double or nothing? Shall we continue and play for two four-in-a-rows?"

Schwartz says: "You're on!"

After another flurry of moves F'red' announces "Ha! Connect Four, all tied up! Next one wins!"

A stressful couple of turns later Schwartz proudly declares, "Gotcha again!" but Fred complains "No! You can't play there, that's connect 5! That's against the rules!" Schwartz says, "Ok, then I'll play here, Connect Four!"

Fred says "Aw nuts, and I would have gotten one on my next turn too."

Schwartz says "I'm glad I got to play -- the board at this point is completely determined, and I wasn't going to even get another turn!"

Fred said "It was pretty amazing that we got this far at all! We'll have to play again some time. Congratulations. Great game!"

Here is the board after the Schwartz second connect four, with almost all of the rest of the squares now given.

Can you determine what moves occurred in what order?