Contact Word Game & Prefix Forcing
Guess a hidden word letter by letter, plus the measurement: a third of the dictionary can never be pinned down, and the plural is why.
A word is hidden and its first letter is shown. Guess words that start with what is on display; reveal another letter when you are stuck. The count underneath is how many words in the game's list still match. Nothing is uploaded.
Each letter collapses the field
Measured across all 274,804 dictionary words of three letters or more, here is how many rivals the average word still has after each letter is given away:
| Letters revealed | Words still matching, on average | |
|---|---|---|
| 1 | 16,156 | |
| 2 | 2,923 | |
| 3 | 489 | |
| 4 | 120 | |
| 5 | 42 | |
| 6 | 13 | |
| 7 | 8 | |
| 8 | 5 |
One letter leaves about 16,156 candidates and five leaves 42. The collapse is far faster than it feels while playing — the bar is on a log scale, or the later rows would be invisible.
But a third of words are never pinned down at all
A word is forced when some prefix of it belongs to no other word. Of the 274,804 words, 98,440 — 35.8% — have no such prefix at all. Every prefix they own is shared with something longer, so the revealer never runs out of letters to give and the word is never cornered. The question "how many letters before it is forced" has no answer for them.
For the 176,364 where it does, the mean is 9.06 letters and the median is 9. Not one word in the dictionary is forced by its first letter alone — there is no letter that starts exactly one word. The commonest case is 8 letters, at 15.5%:
| Letters needed | Share of the words that can be forced |
|---|---|
| 5 | 5.0% |
| 6 | 9.6% |
| 7 | 14.1% |
| 8 | 15.5% |
| 9 | 14.9% |
| 10 | 13.1% |
| 11 | 9.7% |
| 12 | 6.8% |
| 13 | 4.5% |
And the reason is the plural
The words that escape are not obscure. 93.3% of them are explained by a single suffix sitting beneath them, and four fifths by one letter:
| Suffix beneath it | Share of never-forced words |
|---|---|
| −s | 79.8% |
| −es | 7.9% |
| −ly | 4.5% |
| −ing | 0.6% |
| −d | 0.2% |
| −y | 0.2% |
| −er | 0.1% |
| −ed | 0.0% |
"Aardvark" cannot be forced because "aardvarks" is in the dictionary. Add an s to a noun and you have made it uncornerable — which is the commonest possible reason rather than a rare one. Every one of the 98,440 was checked to have a longer word beneath it, which is the definition holding rather than a coincidence.
All of this is computed at build time from the word list already in this project, not frozen into the page — the whole prefix map takes under half a second to build, so there is nothing here that can go stale. The game above runs on a small curated list instead, so the four megabytes of dictionary never reach your browser.
How to use
- A word is hidden and its first letter is shown.
- Type a word that starts with the letters on display.
- Press Reveal a letter when you are stuck.
- Watch the count of matching words collapse as letters appear.
- Press New word to start again.
Frequently asked questions
How many letters does it take to pin a word down?
About nine. Across the 274,804 dictionary words of three letters or more, the mean shortest prefix belonging to a word alone is 9.06 letters and the median is 9. Not one word is forced by its first letter, because no letter starts exactly one word.
Can every word eventually be forced?
No, and this is the part the question usually misses. 98,440 words — 35.8 per cent of the dictionary — have no prefix belonging to them alone. Every prefix they own is shared with a longer word, so the revealer never runs out of letters to give and the word is never cornered.
Why can those words never be forced?
The plural, mostly. 93.3 per cent of them are explained by a single suffix sitting beneath them, and 79.8 per cent by adding s alone. Aardvark cannot be forced because aardvarks is in the dictionary. Add an s to a noun and you have made it uncornerable.
How fast does revealing a letter narrow things down?
Violently. One letter leaves about 16,156 candidates on average, three leaves 489, five leaves 42 and eight leaves under five. The first few letters do nearly all of the work, which is why the game feels stuck long after the field has actually collapsed.
Where do the numbers come from?
They are computed at build time from the word list already in this project, not frozen into the page. The whole prefix map takes under half a second to build, so there is nothing here that can go stale.
Does the game use the whole dictionary?
No, and deliberately. The full list is about four megabytes and would have to be downloaded to play, so the game runs on a small curated list of ordinary words. The test suite checks every one of them is a real dictionary word and that the big list never reaches your browser.
Does this send anything anywhere?
No. The game runs entirely in your browser and nothing is uploaded.
🔒 This tool runs entirely in your browser. Nothing you enter is uploaded, logged, or stored.