Catchup

Just build the largest group. But if you take the lead, your opponent gets an extra move.

This game has never appeared in a previous The Genius ORG before. This game was invented by Nick Bentley, and was a finalist in the Thousand-Year Game Design Challenge in 2011.

GAME RULES

⚙️ Setup and terminology

The game takes place on a hex board with 5 hexes a side. The board has a coordinate system: the rows are labeled A-I, and within each row, the cells are numbered starting from 1 on the left. During a match, only the row labels on the left are visible; the coordinates will not be present. In addition, there is also a score track for both players, explained below.

Throughout the game, a hex can be empty, or filled by a piece of a player color. A connected group of pieces of one color is a group; note that a single piece by itself also counts as a group. (Groups are maximal, in the sense that a group is composed of as many pieces as it can. For example, a group of two pieces does not also count as two groups of one piece each.) The size of a group is the number of pieces it has.

Each player also has a score, which is simply the size of their largest group. However, at the beginning of the game, both players begin with a score of 1, even though they don't yet have any piece on the board. The players' scores are kept track by the score track.

A player is leading for a turn if their score increased, and is now greater than or equal to the opponent's score. For example, from a score of 3-5, the first player makes a move that changes the score to 5-5. Then the first player is leading for the turn. On the next turn, the first player is no longer leading unless they increase their score again.

🧠 On your move

Players alternate turns, starting from the starting player. On the first turn of the starting player, they play one piece anywhere on the board.

For all other turns of the game, on your turn, you may place one or two pieces on the board. However, if the opponent was leading on the previous turn, you may also place three pieces on the board. You cannot pass your turn or place more than three pieces in a single turn.

You may place your piece on any empty hex on the board. If you're placing multiple pieces, they must go to different hexes.

After you have finished your turn, your score might be updated; if your largest group size is greater than your score, your score is increased to match your largest group size. This might cause you to be leading (which lets the opponent place three pieces on their next turn).

💎 Winning

The game ends when the board is full.

You win if your largest group is larger than your opponent's group. In case of a tie, compare the second-largest group; you win if yours is larger. In case of a further tie, compare the third-largest group, and so on. If a player doesn't have a group to compare with, their size is 0.

As an example, suppose you have group sizes 11-8-8-3 and your opponent has group sizes 11-8-7-4-1. Then you win as your third-largest group 8 is larger than the opponent's 7. Had your opponent have 11-8-8-3-1 instead, your opponent would have won as their fifth-largest group 1 is larger than your 0 (you don't have a fifth-largest group).

ADMINISTRATION

🏷️ Writing your move

Your move must consist of all the coordinates of your pieces. However many coordinates you write down is taken to be the number of pieces you wish to place; that is, don't split a two-piece move into two posts of one piece each. All pieces must be on different empty hexes, and you are only allowed to place three pieces if your opponent was leading the previous turn.

👁️ Available information

There is no hidden information. All information is public. You should make your moves in the public game room.

After each move, the current board will be posted. It will also be announced when a score has increased, and if that means the opponent was leading.

⌛ Timing

You have the standard time controls. You have 1 minute per move, plus a time bank of 5 minutes.

CLARIFICATIONS

📌 Examples

The following is an example game between Red and Blue. It is Blue's turn, and on the previous turn, Red played B4 and B5, which did not cause Red to lead.

Blue plays on D7 (connecting the two groups on the right) and F8. Blue's score rises to 4; this causes Blue to be leading, which allows Red to place three stones on the next turn. (Recall that tying the score still counts as leading. Also note that, had the game ended now, Blue's 4-3-1-1 would lose to Red's 4-3-2, so leading does not mean winning at the end of the game.)

Red plays B3 (connecting the two groups on the top), C1, and D2. Red's score rises to 6; this causes Red to be leading.

Blue plays F2, G7, H6. Blue's score rises to 5, but this does not overtake Red, so Blue is not leading; Red may only play two spaces next turn.