How to play Connect Four

Connect Four

Drop a disc, make a line of four. Simple enough to teach in a sentence, and solved to the point where the first player wins with perfect play.

The grid stands upright: seven columns wide and six rows deep.
On your turn, drop a disc into any column that is not full. It falls to the lowest free slot, so you choose the column and gravity chooses the row.
Four of your discs in an unbroken line wins: along a row, up a column, or on either diagonal.
If the grid fills with nobody having made four, the game is a draw.

Going first is a real advantage here. The seed decides who gets it, and it is published at the end so you can check it was not decided any other way.

Against a person or the bot. The bot needs no account and starts at once. To play a person, be rated and keep your games, you need an account: an email address and a password.
At your own pace. Every move has a deadline you both see, from five minutes to a week. A game can take an evening or it can take a fortnight.
Nothing to buy and nothing to win. No stakes, no prizes, no boosts, no undo. The only thing on offer is a place on a leaderboard, and only if you want one.
Every game can be checked. Anything decided by chance comes from the game's seed, and the seed is published the moment the game ends, so any finished game can be replayed and verified by anyone. See fair play.