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Shrdlu

A fifteen-card game about fitting letters into boxes
15 cards, 2+ players, 5 to 20 minutes
Monday the 20th of September 2021

Shrdlu is a game of finding a five- or six-letter word that fits into a set of randomly-dealt constraints. It's a print-and-play deck of fifteen cards.

Gameplay

Shuffle the deck and deal out a row of five cards. (If one of those cards has the "deal out a sixth card" instruction, deal out a sixth card.)

Players then race to think of a word where each letter obeys the constraint on the card in the corresponding position, with asterisks allowing any letter.

An example spread

ETAOIN / * / ONLY 1 OF THIS LETTER / * / ALPHABETICALLY LATER THAN PREVIOUS LETTER

This requires a word that starts with E, T, A, O, I or N; whose third letter only appears once; and whose fifth letter is alphabetically later than its fourth. The second and fourth letters can be any letter, and the word must have five letters in all.

A valid answer would be NIGHT.

The first player to call out a valid word wins the round.

The winner of a round takes the leftmost card of the row and keeps it face-down in front of them for scoring. Take the other cards of the row and put them onto the bottom of the deck.

If nobody can think of a word that fits the dealt cards, players can agree as a group to shuffle the row back into the deck and re-deal.

After eleven rounds (when there are no longer enough cards to deal out another round), the game ends and the player who took the most face-down cards wins. If tied, the tied players reshuffle the deck and play a final tiebreaker round.

The numbers

Bearing in mind the interchangeable asterisks and the possibility of dealing a sixth card, and the unusual final round possibility of "deal a sixth" plus four asterisks, there are (if I've got this right) 306,201 distinct card spreads possible in the game of Shrdlu.

Of these, only 279 have no dictionary solution (at least according to the Collins Scrabble dictionary), meaning that 99.9% of card deals have at least one possible answer. Although some of those answers may be obscure dictionary words that nobody at the table will actually know.

Playing online

You can use the Shrdlu Card Server to try the game out, or to play the game around a single phone screen if you don't have a deck printed out.

You can play the game remotely on playingcards.io by importing the shrdlu.pcio game file into a room. Players should take cards into their hands when they win a round, and must hit the "Deal a 6th card" button manually if the "deal out a sixth" card appears in the spread.

Daily Shrdlu #919

This is today's random spread of cards. The 0.1% of deals with no dictionary-recognised answer are skipped, so it has at least one solution.

The game of Shrdlu is © Kevan Davis 2021. This is v1.3 of the game rules, last updated 8 November 2023.
(v1.3 swaps out the "repeat any of the final three letters" card for a second "repeat any letter", and changes to more of a letterpress look. Since this change brings the solveable deals up from 98.7% to 99.9%, the rule about calling unsolveable deals was dropped in favour of just agreeing to abandon the round.)
Questions? Feedback? Visit the forums for Shrdlu on BoardGameGeek.