Ttakji · Slam the edge and flip your opponent's tile
Ttakji is a Korean children's game played with square tiles of folded paper. In Omokboard's version each player starts with 5 tiles. The defender puts one tile on the ground, and the attacker slams their own tile down on it. Each tile on the ground has one side lifted slightly off the ground, and only that side casts a wide, dark shadow.
Each hit takes two steps. First tap near the tile on the ground to set your aim (tap again to move it). Then press "Hit" or the Space bar: the power gauge swings between 0% and 100%, and the moment you press again sets the power. Past 90% the needle moves more than twice as fast, so stopping it right at the top is hard.
A real ttakji flips or not depending on how the paper bends, the ground, and the rush of air. A screen can't copy all of that, so Omokboard turns where and how hard you hit into a flip chance, then settles it with one random number. The formula and table below are Omokboard's rules, not real physics.
Flip chance = 92% × position score × lifted-side factor × power1.5
Flip chance by position, power, and side (rounded to whole percent). Stopping the gauge at 90% gives 79% just inside the lifted edge and 51% on the other sides.
| Where you hit (center to edge = 1) | Lifted side, power 75% | Lifted side, 100% | Other sides, 75% | Other sides, 100% |
|---|---|---|---|---|
| Near the center (0) | 7% | 11% | 5% | 7% |
| Halfway to the edge (0.5) | 18% | 28% | 12% | 18% |
| Just inside the edge (0.85 to 1) | 60% | 92% | 39% | 60% |
| Just past the edge (1.15) | 36% | 55% | 23% | 36% |
| A bit further out (1.3) | 24% | 37% | 16% | 24% |
| Far outside (1.6 or more) | 0% | 0% | 0% | 0% |
Each tile lands at a slight angle (between -18° and 18°). The edge is measured along the tile's own four sides, not the screen's, so line up your aim with the way the tile is turned. The lifted side changes with every new tile, too.
The Encyclopedia of Korean Culture describes ttakjichigi as a children's game: a paper ttakji is placed on the ground and another is slammed down beside it, and if the tile on the ground flips over or is knocked past a drawn line, the hitter takes it. The loser of rock-paper-scissors puts a tile down first, and a hitter who flips a tile with the rush of air takes it and keeps hitting. Some ttakji are folded from thick paper on all four sides, others are cut from printed paper, and some regions call the game ttaegichigi or pyochigi. (Source: Encyclopedia of Korean Culture, "Ttakjichigi", in Korean)
The same entry notes regional rules such as knocking the tile past a line, winning when your tile slides underneath, and losing yours when it lands on top. Omokboard uses only the flip, the best-known rule, and instead of rock-paper-scissors the first hitter alternates every game against the AI and every rematch online. The lifted-side rule adds the feel of hunting for a tile that isn't lying flat.
The AI uses exactly the same flip formula as you. Difficulty comes down to whether it spots the lifted side and how steady its aim and power are. Easy ignores the lifted side and hits anywhere on the tile at 42 to 92% power. Normal goes for the lifted side about half the time, with a shaky hand and power around 86%. Hard always aims just inside the lifted edge, with a steady hand and power around 92%. On its turn the AI shows its aim and gauge, then hits about a second later.
Real flip rates over 10,000 hits per level, and 1,000 AI-vs-AI games per pairing (remeasured October 31, 2026 with the lifted-side rule, first hitter alternating every game):
| Level | Flip rate |
|---|---|
| Easy | 25.1% |
| Normal | 51.3% |
| Hard | 73.6% |
| Matchup | Result | Hits per game (avg) |
|---|---|---|
| Hard vs Normal | 900 wins, 100 losses | 15.0 |
| Normal vs Easy | 979 wins, 21 losses | 23.7 |
| Hard vs Easy | 994 wins, 6 losses | 11.1 |
| Normal vs Normal | first hitter 557 wins, 443 losses | 28.8 |
With equal skill, hitting first is a small edge (557 of 1,000 games). Because a flip lets you keep hitting, a slightly better flip rate turns into a much bigger win rate. A person who finds the lifted side every time and stops the gauge just before 90% flips 79% of the time, better than the Hard AI. Measurements for the other games are in AI Difficulty Benchmarks.
Create a room and send the 6-character room code or link to play a friend in real time. The room creator (red) hits first in the first game, and the first hitter switches with every rematch.
Online, the server draws the random number that decides each hit. Your aim and power go to the server, which attaches a random number and sends the same thing back to both browsers. Each browser then runs the formula above and gets the same result. The tile's angle and lifted side are fixed by its place in the order, so both screens match. Neither browser can pick the number, so the luck is fair and both screens show the same play. It works the same way as Yut Nori, where the server only throws the sticks.