Codenames: Duet

Edition and setup: Use the original June 2017 CGE rules. Deal 25 word cards into a 5×5 grid, set out 15 green agent cards and the assassin card, and place a random double-sided key so each opposite side sees only one face. The standard time bank contains nine bystander-side-up tokens; leave the other two in the box. Ten- or eleven-token easier missions are optional settings chosen before play, not extra time added midway.

Goal and judging side: Each face shows nine green words and three assassins, with three shared green positions making 15 distinct targets. Your visible green words are for your partner to guess. When you guess, only the clue-giver's face matters, regardless of whether your own face marks the word green, tan or black. A green-covered word is solved for both sides. Do not disclose which words overlap.

Clues: Either player may give the first clue; normally alternate afterward. Give exactly one word and one number without extra explanation. The number indicates associated words, not a second semantic clue. Use meaning rather than position, initials or word length. Letters or numbers can themselves be meaning-based clue words. Do not use forms or compound components of visible words, or add information through accents, inflection, singing or inappropriate foreign translations.

Guessing: The guesser must touch at least one word as an official guess. Green on the clue-giver's face receives an agent card and allows another guess; the clue number is not a maximum. Black immediately loses the game. Tan ends the turn: take a timer token from the bank, put it bystander-side up on that word and point its arrow from the clue-giver toward the guesser. Merely discussing a possible word does not make it an official guess.

Ending turns and switching: After one or more correct guesses, voluntarily stop by taking a bank token checkmark-side up. A bystander already spends the turn's token, so do not take an additional one. Normally switch clue and guessing roles. Once all nine green words on one face are covered, its holder must announce that the partner has no words left to guess. The partner then gives clues on all remaining turns so the other side can finish.

Marked words and earlier clues: A word marked as a bystander in one direction may still be guessed from the other direction. If later green, cover it with an agent and put the old token on top. If a bystander both ways, use a second opposite arrow and arrange the two tokens to cover it. One directional token does not remove a word. Guessers may use any earlier clue, not only the newest one.

Communication and larger groups: Never reveal your key colors, advise when to stop, use reactions to reveal an unintended correct guess, or report a remaining count before all your visible greens are covered. With more players, divide into two opposite sides, each seeing one face. Guessers may discuss without revealing their own face; clue-givers may quietly discuss or write suggestions without letting the opposite side hear. Group size does not add tokens or clues per turn.

Sudden death: When the last timer token is spent with targets left, give no new clue. If one side still has words to guess, it guesses; if both do, either may guess in any order without alternating, but no guessing-strategy discussion is allowed. Resolve one guess at a time using the other side's face. Any incorrect guess, including a bystander, loses immediately. Finding the final remaining green wins together.

Victory and standard-mission score: Covering all 15 agents wins; an assassin loses. For a successful standard nine-token mission, score three per token left in the bank and one per checkmark token taken after correct guesses. Subtract one if sudden death was needed. The final normal winning turn also spends a token, so do not leave that token in the bank for an extra three-point reward. This evaluates a successful team's performance, not a way to offset failure.

Invalid and zero clues: An accidental invalid clue first discards a bank token as a penalty, then the guesser proceeds as if the clue were valid; normal turn end usually spends another. If too much information was exposed, the rules suggest restarting. Zero is a legal number for words to avoid, but still requires at least one guess. Do not use it to skip without risk or encode another clue. Agree on any relaxed naming or wordplay rules in advance.

Optional Mission Map: Its two parameters set total turns and acceptable bystander mistakes. Set that many tokens, with the allowed-mistake number bystander-side up and the rest checkmark-side up. Voluntary stopping prefers checkmarks; a bystander uses a bystander token. Once none remain, a bystander costs two checkmarks from the bank, flipped and stacked on that word. Exactly exhausting the bank permits sudden death; needing two when only one remains loses immediately. Assassins still lose regardless of tokens.