Mental Janggi

MENTAL JANGGI

When capturing pieces is all about performing well in mental games, what risks are you willing to take?

This game was invented by me, brand new for this tournament. The main inspiration is from Human Janggi, a game used in the show Society Game S1E1; the main rules are fairly similar, but adapted for a one-player format.

The goal of the game is to either get your king to the opposite side of the board, or reveal the opponent's king. But playing well in this janggi game requires mental contests.

GAME RULES

⚙️ Setup and terminology

The game takes place on a 6×9 board. The board has a coordinate system, where the rows are labeled A-F and the columns numbered 1-9. Rows 1-2 are the home area for the left player; rows 8-9 are the home area for the right player.

In addition, the board features two different floors. The cells A3-7, B4-6, E4-6, F3-7 are on the second floor; all other cells are on the first floor.

Each player begins with a set of 13 pieces. One piece is the king. The other 12 pieces are mental pieces; there are 3 pieces each of logic, mathematics, memory, observation.

Before the game, each player begins their setup. Discard 2 mental pieces, then number the remaining 11 pieces using the numbers [0, 0, 0, 0, 1, 1, 1, 2, 2, 3, 4] and place them in your home area. You may place your pieces in any way, as long as each square has at most one piece (one square will be empty).

The following is an example of a valid way to number and place the pieces for the left player.

Pieces you discard are revealed to the opponent when the game begins, and then removed entirely from the game, as if they don't exist. The other pieces on the board have a number (0-3) and an identity (the king or one of the kinds of mental pieces). All pieces on the board start out unrevealed; they only show their number, not their identity. Therefore, in the example above, the board would look like this to the opponent:

An unrevealed piece is a piece that only shows their number. A revealed piece is a piece that shows both their number and identity.

🧠 On your move

On your turn, you must move one of your pieces; you may not pass your turn. A piece may move forward (towards the opponent's home area) or sideways, but not backward. If you move a piece on the same floor, you may make two consecutive moves using the same piece; the square in between the two moves does not have to be empty. If you move a piece to a different floor, you may only make one move.

There is a restriction to avoid stalemates. If you and your opponent both made purely vertical moves (moves that stayed within the same column) and neither move caused any battles (see below), your next move must have a forward component.

After your move, if your moved piece is adjacent (sharing a side) with any opponent piece that is on the same floor, there will be a battle, which will remove one piece from the board. If it is adjacent to multiple opponent pieces, there can be multiple battles; you choose the order of the battles, and you will continue with battles until there is no more battle to be done (because either your piece is gone or all your adjacent opponent pieces are gone).

Each battle ends with one piece removed from the board.

• If you lose your piece, you face a humiliation penalty: you must reveal the piece you removed (if it is not yet revealed).
• If the opponent loses their piece, there is no such penalty. If their piece is unrevealed, it will remain unrevealed for the rest of the game.
• If the removed piece is a king, the game ends; see below.

After you complete all battles, your turn ends. If your moved piece is now in the opponent's home area and hasn't been removed by battles, you gain a bonus: you may swap any two numbers among your pieces. This may even involve pieces that have been removed from the board due to battles earlier. (But this cannot involve pieces you discarded in setup; they do not have numbers and they are not part of the game.) You may move with this piece again in a future turn, and if it survives again, you will get the bonus again.

🔍 Battle

A battle happens when two pieces, one by each player, are adjacent and on the same floor. A battle consists of three steps:

1. Intimidation step
2. Selection step
3. Contest step

The attacker is the player that has the turn (and thus the one that moved a piece to cause a battle), and the defender is the opponent.

In the intimidation step, the piece with a lower number might end up revealed. Between the battling pieces, the player with a higher number gets a number of chances to guess their opponent's piece, assuming it is not yet revealed. The number of chances given is equal to the difference of the numbers. (If the two pieces have the same number, no intimidation step occurs.)

If you are given some chances to guess, you may name a kind of mental piece for every guessing chance you have. You cannot name the king this way. If any of your guesses is correct, the opposing piece is revealed; if all of them are incorrect, you are told so and it remains unrevealed.

The selection step determines which kind of mental contest the battle will be. After the intimidation step is done, the attacker chooses either the attacking piece or the defending piece. That piece is revealed (if it's not yet already revealed), and then the contest will be of that type.

As an example, suppose the attacking piece is a 3, revealed to be a memory game, and the defending piece is an unrevealed 1. As the player with the higher number, the attacker gets to guess, with a total of 3-1 = 2 chances. The attacker names "mathematics" and "memory"; both are wrong. The attacker now knows the defending piece is a logic piece, an observation piece, or the king. The attacker now may select to either play using the attacking piece (a memory game), or using the defending piece (a logic game, an observation game, or a win by revealing the opponent's king; see below).

🔍 Contest

The contest step is the last part of a battle, where both players will compete in a mental task to determine the winner of a battle. Contests vary tremendously in structure, but in general, contests demand speed and accuracy.

When a contest is declared, I will first post the general rules of the contest. You are given one minute to understand the rules and form a strategy; after the one-minute period, I will post the actual problem for the contest. You are allowed to ask me to pause the timer in case you don't understand a particular terminology. However, this rule is not meant to be abused to grant you extra time, it is only for genuine clarifications; if I determine you are doing it for stalling, I will go ahead and post the problem anyway.

In some contests (most often memory contests), you will first receive supplementary material that you will be able to look at before you even get the rules. If you will receive supplementary material, you will be informed of such so that you can be ready.

While contests vary in structure, the most common format is that you will be posed a problem, and you have to give the correct answer; the first person to do so wins. The most common penalty of a wrong answer is that you are locked out and cannot give an answer for the next 30 seconds.

Contests often have a time limit, usually 5 minutes. If a contest is not won by either player before the time limit, the defender is declared winner by default.

The different kinds of contests are explained, with examples, in the contest kinds heading below.

The winner of the contest is the winner of the battle; the loser removes their piece from the board, as explained in the on your move heading above.

💎 Winning

There are three ways you can win:

• Bring your king to the opponent's home area, and end your turn (i.e. complete all battles).
• Make your opponent reveal their king (because you are battling it and you choose the defending piece for the selection step).
• Make your opponent lose their king (because it is involved in a battle and loses).

Note that any other piece that reaches the opponent's home area doesn't win you the game; only the king matters. However, as explained in the on your move heading above, a piece in the opponent's home area gives you a bonus of swapping numbers.

CONTEST KINDS

Logic. A logic contest will require you to use your logical reasoning skills; often, this means solving a logic puzzle. Logic puzzles come in many forms: pencil puzzles such as Sudoku, truth-teller puzzles such as knights and knaves problems, logic grid puzzles such as the zebra puzzle, and so on. Compared to mathematics, a logic contest uses minimal math, usually at most the four basic arithmetic operations.

Mathematics. A mathematics contest will require you to perform quick and accurate computations in some kind. Mathematics is a very wide subject, made of many topics. Some very basic concepts, such as the four basic arithmetic operations, should be expected. In addition, these are some topics that you might want to prepare for: modulo (remainder operation); divisors of a number and the concept of prime numbers; number bases such as binary; basic geometry involving lengths, areas, and angles; basic combinatorics such as counting the number of ways to do something.

Memory. A memory contest will require you to memorize something in short order, and then recall information from that. The thing being memorized can cover a wide range: pictures both abstract (letters and shapes) and real (actual objects and landscapes), sequences of letters/numbers/words, and so on. Normally you are presented with the thing to be memorized first before you are presented with the question.

Observation. An observation contest will require you to use your observational skills, identifying things in pictures. The main difference with memory contests is that you get to see the picture all the time in observation contests; at the same time, it also means the questions being asked might be significantly more complex. Pictures may involve colors; please tell me beforehand if you have a case of colorblindness. The following example uses all the possible colors that will appear, so if you can distinguish them, it's fine.

ADMINISTRATION

🏷️ Writing your move

For setup, use any format that is clear enough. All 11 pieces you place must include their respective identity, number, and location.

For the janggi portions, submissions must include the following:

• Moving a piece: include the origin and the destination.
• Declaring battles: select one opposing piece to be battled, if there are multiple.
• Guessing during the intimidation phase: name the kinds of mental pieces you want to guess.
• Selecting contest kind: choose either attacking piece or defending piece; if either one is revealed, you may also name the revealed kind to use it.

If you get to submit for multiple of the above, please do so in a single post to not delay the game unnecessarily. For example, if you are about to battle multiple pieces, you have one in mind for which one to go for, and you have a higher number than the opponent, you can move, declare battle, and guess all at the same time, in a single post. (Then you will wait for my reply on the guess before you proceed to select the contest kind.)

For the contest portions, submission rules are generally described by the contest rules. In general, during a contest, anything you post that might be construed as a submission is counted as such, and will count against you if it's wrong.

👁️ Available information

In the janggi portion, the public information includes the current board, the numbers on all pieces on the board and removed, as well as the identities of all revealed pieces. The identities of unrevealed pieces are hidden. You should make your janggi moves in the public game room, except for the setup which is in your private submission channel.

After each move, the current board will be posted.

The contest portions will have their own rules, but I expect everything to be public (with an obvious exception of any memory component).

THIS IS PARTIALLY A MEMORY GAME. In general, notes are allowed, but if the contest rules specify notes are not allowed for the contest (usually in memory contests), you may not refer to any notes for the duration of the contest, not even notes that are not related to the contest.

⌛ Timing

For the janggi portion, you have standard time controls. You have 1 minute per move, plus a time bank of 5 minutes. If you are making multiple battles in a single turn, after each battle, your turn timer is replenished to 30 seconds if it was lower than that. If you get to guess during the opponent's turn, you have 30 seconds (plus your time bank) to guess.

During the contests, no turn timer is running. After the rules for a contest are released, there is normally one minute before the problem is released (unless a player wants to ask for clarifications). A contest also often has a time limit (usually 5 minutes), after which the defending player is declared winner by default.

CLARIFICATIONS

📌 Examples in the contest kinds heading

The examples under the contest kinds heading are examples. They may or may not reflect the actual contests; they are meant to give you an idea of how the various kinds of contests will look like.

📌 Rule change: Battles only on the same floor

A battle is only triggered when the two pieces are on the same floor. Being adjacent but on different floors will not trigger a battle.

This is the same rule as in Society Game that I accidentally omitted.

📌 Rule change: Sliding movement.

When a piece moves, it has to have a path of unoccupied spaces to that position (so no jumping pieces and no diagonal movement if both ordinal directions are occupied)

📌 Clarification: Manual notes only.

You're not allowed to use any notes that act like functions where you put one thing in and get a different thing out.

Pen and paper; Notepad; Excel; Image editors (like paint.net) are all allowed.

Google, calculator, Excel with formulas are not.

As a reminder, during a memory context NO NOTES AT ALL are allowed.