Connect Four Trainer

Exact game solver · threat & parity trainer
Rings mark threats (a square that completes four-in-a-row): red / yellow / both. Solid ring = threat lies on its useful parity (Red ↔ odd rows, Yellow ↔ even rows); dashed = wrong parity, usually only tactical. Keys 1–7 drop a disc.

How to Beat Any Human

0. The game is solved

Red (first player) wins with perfect play, and only by starting in the center column. Starting adjacent to center draws; anything else loses (with perfect play). Take Red when you can, take the center, and never give it back.

1. Threats and parity (the master skill)

A threat is an empty square that would complete your four. Because gravity fills columns bottom-up, as the board fills in a zugzwang endgame, Red ends up claiming odd rows (1,3,5) and Yellow even rows (2,4,6). So a Red threat on an odd row is a long-term winning asset; on an even row it is usually only tactical. The board overlay shows exactly this: collect solid rings, and count your opponent's.

2. When is the game already decided?

Watch the verdict box. Early on the solver reports a heuristic eval; typically by moves 12–16 it proves an exact result ("forced win in N"). Against humans, your edge is knowing the verdict before they do: once you are proven winning, every move you need exists — find it. Once you are proven lost, play the longest defense and wait for their mistake (the trainer shows which defense lasts longest).

3. Standard winning patterns

  • Open three: _ X X X _ — two threats at once, unstoppable.
  • The "7": a horizontal three and a diagonal three sharing stones — creates a double threat.
  • Stacked threats: two of your threats in the same column, yours directly above theirs, or odd-above-even — the lower one poisons the square beneath the upper.
  • Forcing sequences: each threat forces a block; the blocks build your real attack. Practice spotting when a forced sequence ends in an open three.

4. Training regimen

  • Play Red vs Perfect. You should eventually convert a win every game — the win exists.
  • Play Yellow vs Casual/Club and practice punishing inaccuracies instantly (watch for the verdict to flip).
  • After any Mistake/Blunder tag, hit Undo and find the better move before asking for a Hint.
Engine Analysis
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