If played on a bigger board than we have currently, I believe that playing with three players may prove to be an interesting, complex variation on C6.

All rules remain the same, except:

The board is large (39x39 at minimum).

Three players (add a color in).

I've tried this out by myself, and come up with interesting results…

You need 7 threats to win, instead of 3.

An open-3 is a double-threat.

Player 1 makes a triple-threat move - Player 2 can ignore it and force Player 3 to block!

Because of the nature of strength in the turn rotation, it would take 6 games to have an “even” series.

Reading the above, I've just thought of this variation of Connect6:

Player-1 plays 1 stone.

Player-2 plays 2 stones.

Player-3 plays 3 stones.

From then, every player plays 3 stones.

The winner is the one who has 6 (or more) in a row, just like Connect6.

Reading again estevao's post, perhaps he did mean too that every player places 3 stones per turn.

Did you mean that, estevao?

Yes, that's what I meant…I thought I had put it in the original post but I guess I hadn't :P