How to play Just One Letter
Just One Letter is a daily word ladder. You are given two five-letter words and have to get from the first to the second by changing a single letter at a time — and every step along the way has to be a real word. The shortest route is always exactly five steps, and you are allowed ten moves.
The rules
- Change exactly one letter of the word you are standing on to make another real word.
- Every step counts, including the ones in the middle. There is no jumping.
- The shortest route is always exactly 5 steps, every single day.
- You get 10 moves. Run out and the puzzle ends unsolved.
- No take-backs. A move you have played is played. You may walk back to a word you have already used, but it costs a move like any other.
- Guessing costs nothing. If the game does not accept a word, you lose no move for having tried it.
A worked example
Getting from WHITE to SHARD. Green marks a letter that is already where it needs to be; the dot marks the letter that was swapped.
Five moves, so that is a perfect 5/10. Notice that the third move replaces the W — a letter that was never going to survive — rather than working on the end of the word. Knowing which letter to attack first is most of the skill.
How scoring works
Your score is the number of moves you used, out of ten: 5/10, 7/10, and so on. Five is perfect, because five is the shortest route that exists.
That last part is worth being precise about, because it is what makes the score mean anything. Each day's pair is checked against all 14,550 playable words before it is published, and only pairs whose shortest route is exactly five are used. So par is not a designer's guess at difficulty — it is a fact about the puzzle. Nobody can beat five, on any day, with any vocabulary. And because the denominator never moves, your 6/10 and a stranger's 6/10 describe exactly the same amount of work.
Route rarity: the second game
There is usually more than one way to do it in five. On a typical day there are somewhere between one and forty different five-step routes, and all of them score 5/10.
So the routes themselves are scored too. Every word sits in a graph of all the words one letter away from it; some words have twenty neighbours and some have two. A route through the sparse part of that graph is a narrow route, and finding the narrowest one is a genuinely harder achievement than simply finishing in five. It does not change your 5/10 — it is a separate thing to chase once the first game stops being difficult.
When you finish, the game draws the entire solution space: every five-step route that existed that day, with the one you took picked out through it.
Is this Wordle?
No, and the difference is structural rather than cosmetic. Wordle is a deduction game — there is a hidden word, and each guess buys you information about it. Just One Letter is a navigation game — both words are on screen from the first second and nothing whatsoever is hidden.
What makes it hard is the shape of English. Most one-letter changes do not produce a word at all, and most of the ones that do lead somewhere useless. You are not working out what the answer is; you are working out how to get there.
Just One Letter is not affiliated with Wordle or The New York Times. The word ladder itself is much older than either — Lewis Carroll invented the form in 1877 and called it Doublets.
Tips
- Work out which letters have to change. Compare the two words. If four letters differ, you have at most one move to spare.
- The hard letter first. The letter with fewest options is the one that will strand you if you leave it until last.
- A green letter is not safe. Plenty of days require breaking a letter that is already in place and putting it back later.
- Watch the exits. The game shows how many words are one letter from where you stand. When that number drops to two or three, you are in a narrow part of the graph and one wrong step can leave you with nowhere to go.
Common questions
Is Just One Letter the same as Wordle?
No. Wordle is a deduction game — you guess a hidden word and are told how close each guess was. Just One Letter is a navigation game: both words are visible from the start and the difficulty is finding a path between them. Nothing is hidden. It is not affiliated with Wordle or The New York Times.
Why is the shortest route always 5 steps?
Because the puzzle is chosen that way. Each day's pair of words is checked against all 14,550 playable words before it is published, and only pairs whose shortest route is exactly 5 are used. A fixed par is what makes one player's score comparable to another's — nobody can beat 5, on any day.
What is a good score?
5/10 is perfect and cannot be beaten. 6/10 or 7/10 is a good day. You have 10 moves in total, and running out ends the puzzle unsolved, so anything that finishes is a finish.
Can I undo a move?
No. Moves are permanent. You can walk back to a word you have already used, but that costs a move like any other. Guessing is still free: a word the game does not accept costs you nothing at all.
Is it free, and does it need an account?
It is free and there is no account. Your record is kept in your own browser. The game also works offline once it has loaded, and can be installed to your home screen.
Does everyone play the same puzzle?
Yes. There is one puzzle a day and it is the same for everybody, which is what makes scores worth sharing. A new one appears at midnight in your local time.