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A young classic of combinatorial game theory — invented in 2001 and now a fixture of the Computer Olympiad — with rules so spare you can learn them in one breath, yet a strategy that runs surprisingly deep. The board starts completely packed with stones in a checkerboard of two colours, yours and the AI's tangled together everywhere. The twist: every single move is a capture. You slide one of your stones onto a touching enemy stone and remove it; there are no quiet moves, no empty squares to drift into, nowhere to hide. As stones vanish the board fractures into little battles, and the player who runs out of moves first simply loses — so a game of Clobber can never, ever end in a draw. Win games in a row and the AI looks further ahead each time, so your streak is a clean measure of how sharply you can read the wreckage.
You play the teal stones; the AI plays the orange. You move first. The board starts completely full, with the two colours alternating like a checkerboard, so every stone touches enemies on several sides.
Every move is a capture, and that is the only kind of move there is. Tap one of your stones — the enemy stones it can take light up with a green ring. Tap one of those to slide your stone onto it: the enemy stone is removed and yours takes its square. You may only move onto an orthogonally-adjacent (up/down/left/right) enemy stone. You can never move onto an empty square, never move diagonally, and never make a 'pass' or quiet move.
Because every move removes one enemy stone and leaves an empty square behind, the board steadily empties and splits into separate little regions. The game ends the moment a player has no legal capture available. That player loses — and the other wins. Since someone always reaches that dead end, Clobber has no draws at all.
Win a game and the next begins immediately, keeping your streak alive — your score is how many you have won in a row. The AI searches one step deeper as your streak climbs, so it sharpens the longer you last. A single loss ends the run; tap Save to send your streak to the Hall of Fame.
Think of the board as many small fights, not one big one. As stones vanish, Clobber breaks into separate clusters that don't touch each other, and each one is its own little battle that will end on its own. The whole game is really about who runs out of moves last across ALL the clusters at once, so count moves region by region rather than staring at the board as a single mass.
Parity is everything. In a single isolated chain of stones, what usually matters is whether the number of moves left in it is odd or even — that decides who is forced to play the last move there and then fall silent. Try to leave your opponent facing an even total of moves so that they, not you, run dry first. Making or avoiding a capture to flip that count is the core skill.
Don't grab every capture you can. Because you must always capture and can never pass, having moves available is the whole game — a capture that uses up your own future moves can be worse than no capture at all. Sometimes the strong move is the one that keeps YOUR options alive while quietly using up the opponent's, even if a flashier capture is on offer.
Watch for lone stones. A stone with no enemy neighbour is dead weight — it can never move and can never be taken, so it just sits there. Creating an isolated enemy stone (by clearing away the neighbours it needed) removes its moves from the game for good, while keeping your own stones connected to targets keeps your moves flowing. Mobility, not material, wins here.