Play Pong Hau K'i Online for Free
Pong Hau K'i is a tiny two-player trapping game from China, also known as Ou-moul-ko-no in Korea, played on a five-point board shaped like a kite. You and your opponent each command just two stones, and at any moment a single hole sits open. Slide a stone into that hole and a new gap appears where you left. There are no captures and no jumps — you win purely by maneuvering your opponent into a corner where neither of their stones can move.
How to Play Pong Hau K'i
The board has five points joined by seven line segments. There are two top corners, a center, and two bottom corners. The center connects to all four corners. The two bottom corners each have three links (center, the bottom side, and a diagonal), but the two top corners have only two links each: the center and the bottom corner directly below them. Crucially, the two top corners are NOT linked to each other — the top edge is open — so a stone in a top corner can only reach the center or slide straight down.
The pieces are already placed when the game begins: one player's two stones sit on the top corners, the other player's two stones sit on the bottom corners, and the center point starts empty. There is no placement phase, and the top player moves first. On your turn you slide one stone along a connecting line into the single empty point — you cannot capture, jump, or pass. The instant you move, the point you vacated becomes the new empty hole.
You win by blocking: if the player to move has no legal slide — both their stones walled in by occupied neighbors — that player loses immediately. The engine also caps a game at 50 total moves and declares a draw if neither side has been trapped by then.
How to Avoid the Trap (and Set One)
Understand the win condition first: there is no material to win, only mobility to lose. You are trapped when both of your stones have every neighbor occupied. Since only one hole exists at a time, you get caught when the empty point lands somewhere neither of your stones can reach. Every decision is really about who controls access to that single gap.
Fight for the center. The center point touches all four corners and is the most flexible square on the board — the engine itself scores it highest. A stone on the center can almost always respond to wherever the hole opens. The two top corners are the weakest squares because they have only two links and are not connected to each other; a stone stuck in a top corner depends entirely on the center being open to escape, so never let both your stones drift into low-connection corners at once.
The key trap is a 'fork' on the corners: maneuver so the empty point lands on a square your opponent's two stones cannot both cover, forcing one stone to move and then snapping the gap shut so the other has nowhere to go. Always look one move ahead — before you slide into the open hole, ask whether the new gap you create hands your opponent a free escape or lets you seal them in.
Be honest about the math: Pong Hau K'i is a solved game. With only five points and two stones each, the position tree is tiny, and perfect play leads to an endless draw (capped here at 50 moves). The Hard AI runs a full 14-ply alpha-beta search with a 0% blunder rate, so a draw is the best you can force against it; wins come on Easy (30% random moves) and Medium (10%), or when a human lets a stone get cornered. Once you can consistently draw the Hard AI, you have essentially mastered the game.
Frequently Asked Questions
Why are the two top corners not connected to each other?
The board has seven line segments: the left side, the right side, the bottom side, plus two crossing diagonals through the center (each of which is two segments). There is no segment along the top edge. So a stone on a top corner can only slide to the center or straight down to the bottom corner below it — never sideways to the other top corner. That gives each top corner just two links, which is what makes them dangerous and the center valuable.
How can the game end if no pieces are ever captured?
There are no captures in Pong Hau K'i. You win by blocking: when the player whose turn it is cannot move either of their two stones — because every point next to them is occupied — that player loses on the spot. The whole game is about steering the single empty hole away from your opponent's reach.
Why is there only ever one empty point on the board?
Five points hold four stones (two each), leaving exactly one gap. Every move slides a stone into that gap and opens a new gap where the stone came from, so the count never changes. That single shared hole is the entire battlefield — controlling who can reach it is the whole strategy.
Can Pong Hau K'i end in a draw, and how?
Yes. With best play neither side can ever be trapped, so the game would continue forever. To prevent that, the engine declares a draw once 50 total moves have been played without anyone being blocked. In practice two careful players will hit this limit and split the point.
Is it possible to beat the Hard AI, or only draw?
Pong Hau K'i is a solved game that is a draw with perfect play, and the Hard AI searches 14 plies deep with a 0% blunder rate, so it never makes a losing mistake — a draw is the best you can force against it. Wins come on the Easy level (30% random moves) and Medium level (10%), or against a human who lets a stone get cornered.