About Ghost
How to Play
Ghost is a word game for two players. Players take turns adding letters to a growing word fragment, with two goals in mind:
- Don't complete a valid word (4+ letters)
- Don't create a fragment that can't become a word
On your turn, you add a letter to the end of the current fragment. If you complete a word of four or more letters, you lose. If you think the current fragment cannot lead to any valid word, you can challenge your opponent.
Challenges
"I claim this is a word": If you believe your opponent just completed a valid word (4+ letters), you can challenge. If it is indeed a word, they lose. If not, you lose.
"I claim this doesn't start any word": If you believe the current fragment cannot lead to any valid word, you can challenge. Your opponent must then name a word starting with those letters. If they can't, they lose. If they can, you lose.
The Computer Opponent
I have strongly solved Ghost. With perfect play, the first player can guarantee a win. The computer knows, for every possible position, whether it leads to a win or loss with optimal play. The computer will always play optimally, meaning:
- If a winning move exists, it will find and play it
- If the position is losing, it will play the move that delays losing the longest.
A Note on the Word List
Finding the right word list for Ghost was tricky. The list needs to include common words but exclude proper nouns, abbreviations, and clearly non-words. I've done my best to curate the word list, but some questionable entries may have slipped through the cracks.