Word Games
Jotto
Word battleship. You each hide a secret 5-letter word, then take turns probing — and the only clue you ever get is how many letters your guess SHARES with the hidden word (0–5), never which. Name the rival's word first to win. The classic public-domain pencil duel, and pure constraint propagation: each count slices the dictionary into buckets. Solo bot ladder + live 1-v-1 arena.
For Educators
Built for the classroom
Deductive reasoning, set logic, and information theory through play, plus spelling and vocabulary. Each probe returns one number — the size of the set overlap between your guess and the hidden word — and that count is a CONSTRAINT that rules out every word it doesn't match, slicing the candidate list into six buckets (0–5). The deep idea, in the gated theorem: the best probe is the one that splits the still-possible words most evenly — it carries the most information (Shannon entropy, in bits) and the smallest worst-case bucket, exactly the splitter that drives Codebreaker and Twenty Doors. Because overlap is position-blind, anagrams (STARE/RATES/TEARS) are indistinguishable, so the secret pool keeps one word per letter-set — what guarantees every secret is crackable. You may probe with ANY common 5-letter word — about 14,800 are accepted, so kids never have to guess what counts as a word — while every hidden secret is one of 1,076 clean, common, distinct-letter words. Our test proves the splitter cracks every secret within ~8 probes and that the vowel-rich opener PARSE is information-optimal.
Grades 4+ · probe with ANY common 5-letter word — ~14,800 accepted (RETRY, NINJA, FJORD…), no guessing what's "in the list" — while every hidden secret is one of 1,076 clean, common, distinct-letter words · solo is a best-of-3 vs four bots; beat the Cryptographer with the Coach off for the License · live arena is best-of-2 duels with a class ladder.
Three ways to play
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Play solo
Best-of-3 against four bots, all open: Rookie → Prober → Sleuth → Cryptographer, each reading one more layer of the deduction. The 🧭 Coach shows how many words are still possible and the splitter's next probe. Beat the Cryptographer Coach-free to earn the License and unseal the Theorem.
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Host an Arena
Teacher hosts on the projector; students are paired into head-to-head duels and a live ladder ranks the room. Best-of-2, first prober swapped; secrets are auto-assigned and hidden until a round ends.
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Join on any device
Type 5-letter probes; read the shared-letter count and narrow the suspects. Name your rival's word before they name yours.
Run a live class in 5 steps
- Open the Arena — share the 4-letter code / QR / link.
- Students join on any device and are paired into 1-v-1 duels (a bye-bot fills an odd one out).
- Each turn: probe with a word, read the shared-letter count, cross out the words that don't fit.
- Ask the room: which probe would split your suspects most — not the one you hope is right?
- Climb the ladder; send the sharp deducers to the Dojo's Cracker Lab and the entropy theorem.
Tip: host on a laptop or projector (the big screen shows the code, QR and leaderboard); students join on their phones or laptops.
