Decoder

👑 Final Match 1: Decoder 👑

Leverage your puzzle-solving skills to decode your opponent's letters.

This game has inspirations from Letterbox, originally from Zero's Gambit, although this takes more from the variation that appeared in DM Colosseum 2. In turn, Letterbox itself seems to be inspired by the board game Battleships and similar. There are significant differences from both, so make sure to pay attention to the rules. There is also an inspiration to involve solo puzzle missions, which you have completed.

RULES

In this game, you will hold some letter tiles, unknown from your opponent. Your goal is to discover the opponent's tiles before they discover yours. You will take turns inquiring information from your opponent about their secret letters. However, the turns will not necessarily be alternating. The faster you solved the puzzles in your mission, the earlier you get to take your turn.

📌 Regarding timer tanks

Before getting to the actual rules, let's discuss your mission. You have solved 7 puzzles; I have recorded the amount of time you took for each puzzle. Each puzzle has been converted into a timer tank, one timer tank for each puzzle. Each timer tank has a recharge time, which is equal to the amount of time you took divided by 10 seconds, rounded down to the nearest unit (except under 10 seconds becomes 1 unit). For example, if you took 57 seconds to solve the puzzle Arithmetic Box, the Arithmetic Box timer tank has a recharge time of 5 units (5.7 units, rounded down).

You should have already been informed of the official recharge times of your timer tanks. As mentioned during your mission briefing, if you so desire, you are allowed to increase the puzzle timing (and hence the recharge time) of any timer tank to any amount you want, up to a maximum of 5 minutes (300 seconds, 30 units). If you wish to do so, you must do so before the game begins. While you know the recharge times of your timer tanks, you don't know your opponent's.

The timer tanks will be used in two places: at the beginning of the game, to distribute extra secret letters; and during the game, to take your turns. These will be described below.

📌 Selecting letter tiles

This game is played with letter tiles that consist of the English alphabet. The 26 letters are divided into three rarities as below:

• Common (12): A, D, E, G, I, L, N, O, R, S, T, U
• Uncommon (10): B, C, F, H, K, M, P, V, W, Y
• Rare (4): J, Q, X, Z

At the beginning of the game, you will receive a number of letter tiles. You start with a selection of initial letter tiles, consisting of 3 common, 2 uncommon, and 1 rare. But you get additional letter tiles based on your puzzling performance. For each timer tank for which your recharge time is strictly less than 75% of the opponent's, you get one additional letter tile. For example, if for the puzzle Arithmetic Box, you took 57 seconds and your opponent took 70 seconds, then your timer tank has recharge time of 5 units and your opponent 7 units. Since yours is strictly less than 75% of the opponent's, you get an additional letter tile. (Note that, if you compare the actual times, 57 seconds is not strictly less than 75% of 70 seconds. But since the units are the ones compared, and 5 units is strictly less than 7 units, you get the additional tile.)

Among the additional letter tiles you are allowed to take, you may choose any combination of rarities, subject to a total of 3 common, 3 uncommon, and 1 rare. You will know which timer tanks gave you additional letter tiles, but for those that didn't give you any, you don't know whether the opponent did get letter tiles from them or not.

You will first receive your initial letter tiles. Then you may choose any combination of rarities for your additional letter tiles subject to the above conditions, and you will receive them all at once. All tiles you receive are random, but it is guaranteed each tile will only go to at most one of you, i.e. you will not share any tile in common.

Then, from the letter tiles you have (both initial and additional), you pick 6 tiles to form your starting hand. This means if you did not get any additional tile, you must pick everything that you were randomly dealt. Once you have chosen your 6 tiles for your hand, the game will begin.

To recap, information you get:

• You know the recharge time of every timer tank you have. The recharge time for a timer tank is your puzzle solving time is divided by 10 seconds, rounded down to the nearest unit (except below 10 seconds becomes 1 unit).
• You know which timer tanks give you additional letter tiles.
• If a timer tank is not giving you any additional letter tile, you do not know whether it gives your opponent one.
• You learn your initial letter tiles of 3 common, 2 uncommon, and 1 rare, before you select the rarities of your additional tiles.
• You have to choose all the rarities of your additional tiles before you get your additional tiles.
• You know that all letters you received are letters your opponent does not have.
• You do not know what rarities your opponent picked for their additional tiles.
• You absolutely do not know what letter tiles your opponent got or decided to pick.

📌 Taking turns

You will take turns in this game. During your turn, you can learn some information about your opponent's hand or try guessing letters to remove them from the opponent's hand. However, turns are not necessarily alternating. After you make a turn, you must take some time to recharge by using up one of your timer tanks; therefore, the longer the recharge time of your timer tank is, the longer you have to wait before you get to take a turn again.

Formally, each player has a recharge timer. At the start of the game, Dannythus begins with a recharge timer of 0 units, while pseud begins with a recharge timer of 1 unit. Whenever your recharge timer is at zero, you may make a turn. Part of your turn is to use a timer tank; your recharge timer is filled by the recharge time of your timer tank. Whenever both players have their recharge timer being nonzero, both are decreased at the same rate until one of them becomes zero; then they will get to take a turn. If both recharge timers hit zero at the same time, the player that did not take the last turn will get to take a turn next.

Here is an example:

• Danny starts with a recharge timer of 0 units and pseud starts with a recharge timer of 1 unit. Thus Danny makes the first move.
• Danny makes a turn and uses a timer tank with recharge time of 5 units. Danny's recharge timer is now at 5 units, pseud's at 1 unit.
• Both are nonzero and so are decreased at the same rate. Thus pseud's recharge timer will hit zero; at this point, Danny's is at 4 units left.
• pseud makes a turn and uses a timer tank with recharge time of 14 units. pseud's recharge timer is now at 14 units, Danny's at 4 units.
• Both recharge timers are decreased at the same rate. Danny's hits zero next; pseud's is at 10 units.
• Danny makes a turn and uses a timer tank with recharge time of 6 units. Danny's recharge timer is now at 6 units, pseud's at 10 units.
• Both recharge timers are decreased at the same rate. Danny's hits zero next and so will take the next turn, even though the previous turn was also his. pseud's is still at 4 units left.
• Danny makes a turn and uses a timer tank with recharge time of 4 units. Both recharge timers are now at 4 units.
• Both recharge timers are decreased at the same rate, and both hit zero at the same time. The last turn was Danny's, so pseud will make the next turn first.
• pseud makes a turn and fills his recharge timer. Danny's recharge timer is still at 0 units and thus Danny makes the next turn.
• And the game keeps going in this manner.

However, you will not know the opponent's recharge timer. Or even your own, for that matter. You only know when you get to take your turn. You have to deduce what the opponent's timer tanks are based on all the information you receive.

To recap, information you get:

• You know when it's your turn or when it's your opponent's turn.
• You do not know the opponent's recharge timer at any point.
• You do not know your own recharge timer at any point, for that matter.
• You also do not know when a double zero happens (when both players have recharge timers of zero). You will only see that one player takes a turn, then another player takes a turn.

📌 Making a turn

When you get to make a turn, you have one of three choices:

• Ask a word
• Guess a tile
• Restore timer tanks

All three of the choices require you to use up a timer tank, as described earlier. If you only have one timer tank remaining, you must use that last one to restore timer tanks.

Ask a word

You will gain information about what's in your opponent's hand by asking words and getting information based on how many letters of the word are also in your opponent's hand.

Choose one word from the Collins Scrabble Words (2019). (This is a list of words that are accepted in competitive Scrabble in most countries.) There are two requirements of the word: it has to be between 3-15 letters long, and it may not have been used in the game before.

You can go to https://www.collinsdictionary.com/games/scrabble/word-finder to check whether a word is in the CSW; remember that you have to enter a word that is at least 3 letters long in order for it to be acceptable in this game.

From the word you ask, we can derive a count: this is the number of letters in the word that is also in your opponent's hand. If a letter appears multiple times in the word, it is also counted multiple times. For example, if your word is DECODER and the opponent holds A, B, C, D, E, F, then the count of your word is 5: the two D's, the two E's, and the C all contribute to the count.

You will not get the exact count, though. Instead, you will get information in one of the following clues:

• ANY: Whether the count is at least 1 (i.e., whether there is any letter of your word that is in your opponent's hand)
• ODD: Whether the count is odd
• TWO: Whether the count is exactly 2

When you ask a word, you also choose one of the clues that you do not wish to receive. Your opponent will then choose one of the other two clues and give their answer, whether yes (your count follows the clue) or no (it doesn't).

For example, your opponent holds A, B, C, D, E, F. You ask the word DECODER (count 5) and say that you do not wish to receive information in the clue ANY. Your opponent responds by selecting the clue TWO and state that the answer is NO: their count is not exactly two. If your opponent had chosen the clue ODD, the answer would be YES instead, as their count is odd.

This complete exchange constitutes one turn for you.

To recap, information you get and offer:

• You choose one timer tank you wish to use for your next recharge timer.
• You state your word and the clue you do not wish to receive information in.
• Your opponent gives you the clue they pick and their answer for that clue.
• You do not know the exact count of your word. You do not know the answers you would receive in the two other possible clues.

Guess a tile

The way to win this game is to knock out all tiles from your opponent's hand, and the most reliable way to do so is to guess tiles.

Guess one letter of the English alphabet. It will be announced whether it is in your opponent's hand or not.

If your guess is correct, your opponent loses that letter from their hand. Note that this means your future clue answers may change, since the count is only based on the letters currently in your opponent's hand. It also means your past clue answers might become inaccurate with respect to the current hand; be careful.

If your guess is incorrect, you have to give up one of the letters from your hand; it will be revealed to the opponent and it is no longer included in your hand. In addition, your opponent gets compensation for being wrongly accused. They will be shown one random letter, which can be of any rarity, satisfying the following:

• The letter is not among one of the revealed letters (from being guessed or from being given up to an incorrect guess).
• The letter is not in your opponent's hand.
• The letter was not among the letters you saw during setup (initial and additional).

Your opponent is then given the chance to swap any one letter in their hand for this new letter. They may choose not to swap if they so wish. You will not know the decision. It is worth noting that any letter you saw during setup are still guaranteed not to be in your opponent's hand. However, a lot of your past clues will likely be invalidated, making an incorrect guess to carry a huge penalty.

To recap, information you get and offer:

• You choose one timer tank you wish to use for your next recharge timer.
• You state one letter your believe is in your opponent's hand publicly.
• It is revealed publicly whether your guess is correct. If it's correct, your opponent loses that letter and that's all.
• If the guess was incorrect, you must choose a letter from your hand to give up and reveal.
• In addition, if the guess was incorrect, your opponent will also be given one random letter; they may swap one of their current letters for that random letter.
• You do not know what letter was offered to the opponent, nor whether the opponent swapped a letter or which one.

Also note that, unlike in the game Letterbox, there is no way to guess more than one tile at once.

Restore timer tanks

You only have 7 timer tanks. When you use up a timer tank, you cannot use it... until you restore them all.

When you restore, all timer tanks that you have used so far will be restored and can be used again later. However, you used a timer tank to recharge for your next turn; that timer tank is not restored and must wait until you restore next time.

In addition, be careful of your opponent's meddling. Whenever you restore, your opponent may attempt to sabotage. They will guess the total recharge time of all your restored timer tanks. As an example, before this turn, you have used up the timer tanks Arithmetic Box and Bijective Matrix. This turn, you decide to restore these timer tanks (using another timer tank, Encrypted Image). Then your opponent will be guessing the total recharge time of the timer tanks Arithmetic Box and Bijective Matrix.

There is no penalty for an incorrect guess, but a correct guess will let them to sabotage a timer tank. They may choose one of your restored timer tanks (only the tanks being restored this turn, not tanks that were unused or the tank used to recharge your next turn). Its recharge time is increased by 50%, rounded up, although capped at 30 units. For example, a timer tank with recharge time of 5 units gets increased to 8 units (7.5 units, rounded up), and one with 22 units gets increased to 30 units (33 units, capped).

A sabotaged timer tank may keep being sabotaged. Of course, once it hits 30 units, sabotaging it again will do nothing. Your opponent doesn't know that, though.

Therefore, while you might want to make use of your fastest timer tanks, you need to make sure you're not using them so much that your opponent can guess them.

As mentioned earlier, if you only have one timer tank unused, you must use it to restore your timer tanks.

To recap, information you get and offer:

• You choose one timer tank you wish to use for your next recharge timer. This tank is not restored.
• Your opponent guesses the total recharge time of the restored timer tanks.
• If they are correct, they also get to choose one of your restored timer tanks to sabotage.
• They do not know the new recharge time of the sabotaged tank, they only know it's increased by 50%. You do know it as you know all recharge times of your timer tanks.
• I will not keep track of how many times a tank has been sabotaged; it is your job to handle that. I will only keep track of the new recharge times.

📌 Winning the game

You win if your opponent's hand runs out of tiles, whether because you guessed them or the opponent is forced to give up some of them due to incorrect guesses.

📌 TL;DR

Here are the important points:

• You have 7 timer tanks corresponding to the puzzles you solved; the longer you took a puzzle, the longer the recharge time of a timer tank is.
• You're given a selection of tiles of various rarities; the more puzzles you solidly win against the opponent, the more tiles you may select.
• You take 6 tiles from your selection into your hand, secret from the opponent. Your goal is to guess all tiles from the opponent's hands.
• You get your turn whenever your recharge timer is down to zero. Once you make your turn, you must use up a timer tank; the longer the recharge time, the longer you wait until your next turn.
• On your turn, you may decide to ask a word. Give a word and choose one clue you don't want to receive. The opponent will choose one of two other available clues to give to you.
• On your turn, you may decide to guess a letter from your opponent's hand. If correct, they lose that letter from their hand. If wrong, you have to give up one, and they are allowed to swap out a letter from their hand.
• On your turn, you may decide to restore all your timer tanks (other than the one you're using now). Your opponent may guess the total recharge times of your restored timer tanks. If correct, they get to sabotage a tank and increase its recharge time by 50%. No penalty for being wrong.
• You win if your opponent loses all tiles from their hand.

GAME ITEMS

The four game items available in this game are as follows:

• Hand Insurance: This item protects you from suffering some of the effects of an incorrect guess. Use this when you are guessing a tile; this replaces the letter you would give up if you're wrong. If your guess is actually incorrect, you use this item and don't lose any letter tile from your hand. Your opponent still gets the chance to swap a letter tile, though. If your guess is correct, you keep the item; it will not be revealed that you even attempted to use the item.

• New Evidence: This item lets you get two clues at once. Use this when you are asking a word. Your opponent will give an answer to both of the remaining clues instead of just one of them.

• Power Surge: This item lets you quickly restore a timer tank. Use this when you are making a turn. Your timer tank is not used up; it may immediately be used again. You still get recharge timer as usual, though.

• Unexpected Sabotage: This item lets you sabotage an opponent's timer tank on the spot. Use this right after the opponent takes their turn, when you need to provide your decisions for the turn. The timer tank that the opponent used is sabotaged, in the same manner as a correct guess on restoring tanks: its recharge time is increased by 50%, capped at 30 units. This new recharge time is immediately applied for this turn; the opponent must wait out the new recharge time before they get their turn.

ADMINISTRATION

📌 ⏰ Timing

Before the game begins, you may decide to increase your puzzle timing as described earlier in the rules. You may change your mind at any time, but your timing and any increases of it will be locked in approximately half an hour before the scheduled FM time.

The letter selection technically happens before the FM. You may arrive as early as 10 minutes before the scheduled FM time. Once you are ready to begin letter selection, you may state so. You will then get an amount of time to complete your letter selection process. This includes learning the timer tanks that give you additional tiles, seeing your initial letter tiles, selecting the rarities of the additional letter tiles, seeing your additional letter tiles, and finally selecting your hand. You will have until the scheduled FM start time to complete this process, although you will always have at least 3 minutes in case you can't arrive early.

On your turn during the game, you have 90 seconds (1.5 minutes) for your decisions in the turn, and your opponent has 60 seconds (1 minute) for their decisions.

You also have a time bank of 5 minutes. If you run out of time for your decision, you will begin using up your time bank in 5-second increments. If your time bank is depleted and you run out of the time you have for your turn, you lose the game immediately.

📌 🧠 Submissions and allowed tools

The letter selection process is entirely done in your private table channel.

During the game, all submissions are done in the public game room, except when you get the chance to swap a letter (because your opponent made an incorrect guess). The host will take the first legal submission you make, unless you promptly fix the submission (e.g. in case of making a typo or sending a move too early).

The submissions required depend on the action you are doing. On your turn:

• In all cases: state the timer tank you use (the name of the tank). Also, if you want to use Power Surge, state so.
• If you are asking a word: state the word, and state the clue you do not wish to receive. Also, if you want to use New Evidence, state so.
• If you are guessing a letter: state the letter. The host will then tell if it's correct or wrong. If it's wrong, also state the letter you wish to give up, or state you wish to play New Evidence.
• If you are restoring timer tanks: no additional submission.

On your turn, your opponent is expected to respond in this manner:

• In all cases: if they want to use Unexpected Sabotage, they state so.
• If you are asking a word: they state the clue they wish to give. The host will give the answer to that clue. (If you use New Evidence, the opponent doesn't get to make any decision, although they may still use Unexpected Sabotage.)
• If you are guessing a letter, and it is wrong: the host will give the new letter to the opponent. They state whether they wish to swap a letter from their hand, and if so which one. As a reminder, this will be done in private, only to the opponent.
• If you are restoring timer tanks: they state their guess on the total recharge time. The host will state whether the guess is correct. If correct, they state which timer tank they wish to sabotage.

You may use any available tools for note-taking. However, you may not talk to other people or use any automated programs.

📌 📡 Information

The following lists describe who knows each piece of information. If anything is not listed here, feel free to ask.

Timer tank and recharge timer

• The names of the tanks: public
• The recharge times of your tanks: only you know yours, ask any time in private (for the updated times after sabotages)
• Who has the turn: public
• The exact values of players' recharge timers: nobody

Letter tiles in hand

• Whether you win a tile from a timer tank: only you know yours
• The initial/additional letter tiles: only you know yours
• The letter tiles chosen: only you know yours
• Letter tiles revealed, either by being guessed or given up: public
• New letter offered to you for swapping (from incorrect guess): only you know yours
• Decision on whether to swap, and which tile gets swapped out: only you know yours

Turn actions

• The name of the tank being used up: public
• The recharge time of the tank being used up: only you know yours
• Asking a word, the word: public
• Asking a word, the clue you don't want: public
• Asking a word, the clue given and the answer: public
• Guessing a letter, the letter guessed and whether it's correct: public
• Guessing a letter incorrectly, the letter you give up: public
• Guessing a letter incorrectly, the swap: see "Letter tiles in hand" above
• Restoring timer tanks, total recharge time guessed and whether it's correct: public
• Restoring timer tanks, correct sabotage, the tank being sabotaged: public

Miscellaneous

• Your current turn timer: public, ask any time, reminders expected at 30/15/5 seconds
• Your current time bank: public, ask any time, reminders expected at every multiple of 30 seconds

Clarification: You only have 7 puzzles so you can only get 7 letter tiles. There are rules about what if you got more letter tiles; those were left over from when I designed this game with more puzzles, and can be safely ignored.

Update: The rules have been edited to remove the references to this.