Seega▶Play

Each side has 12 stones. You and the computer take turns placing two at a time on any empty square except the centre, which is marked and stays empty until all 24 stones are down. Nothing is captured while placing. The side that placed last makes the first move. In the first game of a run the computer places first, so you move first; after that the roles swap every game.

A move is one step up, down, left or right onto an empty square, never diagonally and never jumping. If your step leaves an enemy stone trapped between the stone you moved and another of your stones on the same row or column, that stone is captured, and one step can capture in up to three directions at once. Only the stone that moves captures: stepping in between two enemy stones yourself is safe, and a stone standing on the centre square can never be captured. If the side to move has no legal step, it is walled in and the other side moves again.

You win by capturing every enemy stone. If 30 plies (15 moves each) of the movement phase pass without a capture, or the movement phase reaches 160 plies, the game stops and whoever has more stones wins; equal stones is a draw. The counter above the board shows the plies since the last capture.

Each win takes you up a level. At level 1 the computer looks one move ahead and plays a random move 35% of the time; levels 2 to 5 read deeper and blunder 20%, 10%, 5% and 3% of the time, and after that the blunder chance shrinks by 40% with every win but never reaches zero. It thinks for at most 1.5 seconds a move. A loss or a draw ends the run. Every win earns a bonus of 4 points for each stone you still have plus 50 minus the moves you made in the movement phase (never below 0). Your score is wins × 1,000 plus ten times your average win bonus, so more wins always rank higher and, between runs with the same wins, cleaner and quicker wins come first.

Tips & strategy

The placement phase decides more than it seems. The side that places last moves first, and in computer self-play between equal opponents that side won about four games in five. When you place last, use your final stones to set up your first steps; when you place first, spend your stones on safety rather than on attack, because your opponent will answer every threat you build.

Look hard at the four squares next to the centre. The first move of the game has to be a step into the centre from one of them, and that step captures any enemy stone beside the centre that has a stone of the mover's colour behind it, two squares out on the same line. So never leave one of your stones next to the centre with an enemy stone right behind it, and when you are the one moving first, try to own a centre neighbour whose step into the middle captures.

Corners and edges are safe ground. A stone in a corner can never be captured, because there is no pair of opposite squares around it, and a stone on an edge can only be taken along that edge. A stone on the centre square is immune as well. Stepping in between two enemy stones is also safe, so you can plug a gap without fear; the real danger is an empty square beside one of your stones that an enemy stone can step into while another enemy stone waits on the far side.

Count the stones and watch the counter. Thirty plies without a capture end the game on count, so once you are a stone ahead you can win by keeping your stones in locked, safe shapes, and when you are behind you have to open lines and force exchanges before the counter runs out. Walling the computer in so that it has no legal step gives you a free extra move every time. Seega comes from Egypt, where nineteenth-century travellers saw it played on grids scratched into the ground with pebbles for pieces, on boards of 5×5, 7×7 and 9×9 squares. Rules differ from place to place, and in some tellings a capturing stone may keep moving; this version uses one step per turn.