How to Play

1The one-minute version

Every day there is a hidden word. It starts at 5 letters and is the same for every player. You guess words to find it, using the familiar three colors as clues. The twist: when you guess wrong, the word does not just sit there. It mutates. It grows one letter longer and rearranges itself into a new real word.

So the word you are chasing keeps changing. Your job is not only to solve it, but to contain it: to box it in so it runs out of room to grow, then finish it off. Play recklessly and it spreads toward its maximum of 10 letters. Play well and you trap it early.

There is no limit on guesses and no way to lose the day. The pressure comes from your score, which is simply how many letters you spent before you contained it. Lower is better.

2The board and the colors

You type a guess and submit it. Each letter is scored with the same colors you know, each dual-marked with a small corner symbol so it reads without color too:

If you type a word that is not in the dictionary, the guess bounces: it is not accepted, it does not count against you, and the strain does not react. So typos and probes for real words cost you nothing. Only valid, submitted words matter.

3The twist: the strain mutates

This is what makes WordStrain different from Wordle. Every time you submit a wrong but valid guess, the strain mutates before your next turn. It follows a strict order:

• It grows. One new letter is added and the letters may rearrange into a new word, now one letter longer. (The new letter can even be a second copy of a letter already present.)
• If it cannot grow, it rearranges only. The same letters shuffle into a different valid word. Same length, new arrangement.
• If it cannot do either, it freezes. It stays exactly as it is.

Every form the strain takes, at every step, is a real dictionary word. It is never gibberish. Crucially, the strain can only become something consistent with what you have already proven. It cannot suddenly contain a letter you ruled out, which leads to the single most important rule in the game.

4Conserved knowledge: what you learn, you keep

Information you earn is never taken away.

• Green letters carry over. When the strain mutates, your greens come with it, already placed on the new board in a distinct outline conserved style. Their position can move, and the game shows you where each went, but you never re-earn them. You can type over a pre-filled green, and a reset restores it.
• Yellow letters must still be in the word. They carry as clues too.
• Gray letters are banned forever. A gray letter can never appear in any future form of the strain. Ruling a letter out is permanent.

Gray works exactly like Wordle's count-aware elimination. If you have confirmed only one E, the strain might still add another. But once you prove a letter's exact count, every extra copy is treated as gray from then on. Every guess you make permanently narrows what the strain is allowed to become.

5The states you will see

There are no hidden counters. You read your progress from how the strain behaves, shown in the status pill and the length gauge above the board.

When you finally guess the word, the run ends and the result reads CONTAINED. The length gauge shows how long the strain is now, from its starting 5 up to a maximum of 10. A shorter strain at the finish is a better result.

6Containment: the real game

Because gray letters are banned from every future form, eliminating letters is how you contain the strain. Each letter you rule out is a letter it can never use to grow. Rule out enough and it has nowhere left to go: first it can only rearrange (CORNERED), then it cannot change at all (STABLE).

This creates a real choice on every turn:

• Guess to solve: use your clues to try to identify the word and end the run.
• Guess to contain: spend a guess deliberately loading in new letters to rule them out, trading a solve attempt for containment.

Two things make this a genuine decision, not a free move:

• Every letter you enter counts toward your score, so a containment guess is never free.
• A wrong guess tries to grow the strain first. A half-measure that rules out some but not all of its remaining growth options just lets it grow anyway, while still costing you letters. Containment only pays off when it closes off every remaining way to grow at once.

You are also not required to reuse your own clues. You may ignore your greens and yellows to pack a guess with fresh eliminating letters, but then it is a poor solve attempt. Solve now or contain now is a real trade. The best players find guesses that do both: informative and eliminating at once.

7Scoring

WordStrain has two scores that measure two different things. They cannot be traded against each other.

Pandemic score (everyone)

Your Pandemic score is the total number of real letters you enter on your First Run, the very first time you play the day's strain.

• Every letter of every valid, submitted guess counts as one. A 5-letter guess costs 5; after the strain grows to 6, your next guess costs 6; and so on.
• Bounced non-words are free. Only accepted words count.
• Reused gray letters still count. If you spend a guess loading eliminated letters to hunt for new ones, those letters count. You chose to spend them.
• Lower is better. It reads as the total spread you allowed before containing the strain.

Your First Run is blind and locked: it starts the moment you begin and cannot be restarted, so your Pandemic score is honest first contact. Because everyone plays the same starting strain, Pandemic scores are directly comparable across all players. Difficulty settings never affect it.

Eradication score (members, the deep end)

When you finish a run you know the final word's full set of letters. But the origin, the hidden 5-letter word the strain grew from, is some subset of those letters in an unknown order. Your Eradication score is the number of the run on which you first open with the origin word (correct letters, correct order, as your first guess of that run). The best possible is 1. Fewer is better; until you get it, it stays blank.

The origin is fixed for the whole day, and replaying re-runs the exact same strain from the same root, so Eradication measures how efficiently you studied the strain until you could wipe it out at the source. This is the members' meta-game; casual replay is always free but earns no score.

8A game, step by step

Here is one full First Run, so you can see the strain move, shown with the real board tiles. The mutations are illustrative: they obey every rule (each new form is a real word, one letter longer, that keeps your greens and never uses a grayed letter), but the exact word the strain picks each day is chosen by the engine from a daily seed. Colors are read against the strain as it is that turn.

How the origin ties in (Eradication)

The strain started as REACT on turn 1. That 5-letter starting word is the day's origin, and you never guessed it, so it stayed hidden. Once you know the full letter set, you can replay and try to open a run with the origin itself:

9Difficulty: the lab notebook

The keyboard wipes clean on every replay, so the first guess of each run is always made cold. Difficulty only changes how much of your own earned history the game hands back, never the puzzle itself:

• Hard: blank board, no notebook. Pure memory and deduction.
• Standard: blank board plus a notebook you fill in yourself.
• Easy: an auto-filled notebook listing the words you have already completed today.

The notebook lists your completed words as plain records only. It is never re-colored against the origin, because clues you earned against the mutated words are not valid clues about the origin. The deduction always stays yours.

10Accounts (what you need for what)

• No account: play the daily First Run and get your Pandemic score. Share your result.
• Free account: save your streak and history, take a place on the leaderboard, and replay past days unranked.
• Member: the Eradication ladder and score, the notebook aids, and the puzzle archive.

You do not need an account to start playing.

11A few strategy tips

• Openers still matter. A strong first guess with common, spread-out letters gives the most information and, if you are lucky, the lowest possible Pandemic score.
• Think about growth, not just the word. A wrong guess will try to grow the strain. Sometimes the better move closes off its growth even if it is not your best solve attempt.
• Gray is a weapon, not a disappointment. Ruling out a common letter the strain wants can do more to contain it than a near-miss solve.
• Containment only counts if it is total. Half-blocking the strain just feeds it a letter for free. Close every remaining path at once, or wait until you can.
• Watch the status pill. SPREADING means it still has room; CORNERED means one more good cut may freeze it; STABLE means stop containing and solve.
• Shorter finishes are better. A solve at 6 letters beats the same solve at 12. The score rewards keeping the strain small.

12Quick reference